Download Preventive Maintenance Support

Reference Materials:
NFPA 1911: Standard for the inspection and
maintenance, testing and retirement of in-service
fire apparatus.
Allison Publications: Mechanics tips booklets and
operators manuals. These maybe downloaded at,
www.allisontransmission.com
Operating Principles : Hydraulic Systems
Hydraulic Systems
PCS = Pressure Control Solenoid
NVL = Neutral Very Low
PSC = Pressure Control Solenoid
NVL = Neutral Very Low
Operating Principles:
Function of a Torque
Converter
Operating Principles:
Components of a Torque
Converter
Operating Principles: Lock
up Clutch Operation
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips
Operating Principles: Driving
Tips Normal PTO Operation
Operating Principles: Driving
Tips Normal PTO Operation
Operating Principles: Driving
Tips Normal PTO Operation
Operating Principles: Driving
Tips Normal PTO Operation
Operating Principles: Driving
Tips Normal PTO Operation
TRANSMISSION IDENTIFICATION
The transmission identification plate (nameplate) is located on the right-rear side
of the transmission. The nameplate shows the transmission serial number, part
number (assembly number), and model number. Use all identification numbers
when ordering parts.
Data Plate Location
Data Plate Model Breakdown
Data Plate Model Breakdown
Data Plate Model Breakdown
Operating Principles:
Water Pump Operations
o Shift Sequence:
1. Stop Apparatus
2. Apply Parking brake and place transmission into neutral
3. Change the Pump engagement control from the road position to the pump
position
4. Place the transmission in drive observing the indicator for 4th gear lockup.
( If the apparatus has a digital display in the shift selector)
5. Observe the Pump engaged light and OK to pump lights are illuminated
6. Verify the speedometer is showing driveline rotation by indicating miles
per hour.
o The Pump is now engaged and ready for operations
Operating Principles: External Component Identification
Operating Principles: External Component Identification
Operating Principles: External Component Identification
Operating Principles: External Component Identification
Operating Principles: External Component Identification
Operating Principles: Shift Selectors Operations
Operating Principles: Shift Selectors Operations
Operating Principles: Shift Selectors Operations
Operating Principles: Shift Selectors Operations
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: 3000/4000 Shift Selector Function
Operating Principles: External Component Identification
Neutral Safety Switch
Operating Principles: External Component Identification
Mechanical Modulator
Operating Principles: External Component Identification
Mechanical Modulator
Operating Principles: External Component Identification
Mechanical Modulator
Electronically Controlled Modulator
Operating Principles: 3000 / 4000 Lockup Mode
Preventive Maintenance Support: PTO Installation
o Gaskets / Sealing Material: Do Not use cork or other
soft gaskets to install a PTO to the transmission PTO
mounting pad. Use only the shims/gaskets listed in
the appropriate parts catalogs.
o Sealing Compounds: So not use sealing compounds,
they are usually incompatible with automatic
transmission fluid.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.4 TRANSMISSION FLUID CHECK
2.4.1 Manual Fluid Check Procedure.
WARNING: To help avoid personal injury or property damage caused
by sudden and unexpected vehicle movement, do not check fluid
level until you:
Put the transmission in N (Neutral).
2. Apply the parking brake and emergency brakes and make sure
they are properly engaged.
3. Chock the wheels and take and any other steps necessary to
keep the vehicle from moving.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
TRANSMISSION FLUID CHECK:
Clean all dirt from around the top of the fluid fill tube before removing the
dipstick. Do not allow dirt or foreign matter to enter the transmission. Dirt or
foreign matter in the hydraulic system may cause undue wear of transmission
parts, make valves stick, and clog passages. Check the fluid level using the
following procedure and report any abnormal fluid levels to your service
management.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.4.2 Cold Check Procedure. The purpose of the cold check is to
determine
if the transmission has enough fluid to be operated safely until a hot check
can be made.
CAUTION: The fluid level rises as fluid temperature increases. DO
NOT fill above the “COLD CHECK” band if the transmission fluid is
below normal operating temperatures. During operation, an overfull
transmission can become overheated, leading to transmission
damage.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
1. Park the vehicle on a level surface. Apply the parking brake and chock
the wheels.
2. Run the engine for at least one minute. Shift to D (Drive), then to N
(Neutral), and then to R (Reverse) to fill the hydraulic system.
3. Shift to N (Neutral) and allow the engine to idle (500–800 rpm).
4. With the engine running, remove the dipstick from the tube and wipe
the dipstick clean.
5. Insert the dipstick into the tube until it stops and remove.
Check the fluid level reading. Repeat the check procedure to verify the
reading.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
6. If the fluid level is within the “COLD CHECK” band, the transmission
may be operated until the fluid is hot enough to perform a “HOT RUN”
check. If the fluid level is not within the “COLD CHECK” band, add or
drain as necessary to bring it to the middle of the “COLD CHECK” band.
7. Perform a hot check at the first opportunity after the normal operating
sump temperature of 71°C–93°C (160°F–200°F) is reached.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.4.3 Hot Check Procedure.
CAUTION: When performing the Hot Check procedure, the fluid
must be at operating temperature to be sure of an accurate check
and help prevent transmission damage. The fluid level rises as
temperature increases. During operation, an overfull transmission
can become overheated leading to transmission damage.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.4.3 Hot Check Procedure.
1. Operate the transmission in D (Drive) until normal operating
temperatures are reached:
• Sump temperature 71°C–93°C (160°F–200°F).
• Converter-out temperature 82°C–104°C (180°F–220°F).
• If the transmission temperature gauge is not present, check fluid
level when the engine water temperature gauge has stabilized and
the transmission has been operated under load for at least
one hour.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.4.3 Hot Check Procedure.
2. Park the vehicle on a level surface and shift to N (Neutral). Apply the
parking brake and chock the wheels. Allow the engine to idle (500–800
rpm).
3. With the engine running, remove the dipstick from the tube and wipe
clean.
4. Insert the dipstick into the tube until it stops. Then remove it. Check
fluid level reading.
5. Repeat the check procedure to verify the reading.
6. If the fluid level is not within the “HOT RUN” band, add or drain as
necessary to bring the fluid level to within the “HOT RUN” band.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.6 FLUID RECOMMENDATIONS
Only use fluids meeting Allison Transmission specification TES 295 or TES
389 in the transmission. For a list of currently approved transmission fluids,
go to the Allison Transmission web site
• Fluids meeting TES 295 specification are preferred over TES 389 fluids
for use in all 3000/4000 Product Family transmission applications.
• TES 295 fluids are fully qualified for Severe Duty and Extended Drain
intervals.
• A fluid meeting TES 295 specification is required in order to use
Prognostics Features in A51, A52, A53 series Transmission Control
Modules (TCMs) calibrated prior to October 09, 2009, if Calibration
Identification Number (CIN) starts with 4A. – The Prognostics packages available in
A51, A52, A53 TCMs calibrated after October 09 2009, to a CIN starting with 4C,
allows a selectable fluid type between either TES 295 or TES 389 fluid.
• A TES 295 fluid allows you to operate at a lower ambient temperature
than a TES 389 type fluid. Refer to Table 2–4.
RECOMMENDED AUTOMATIC TRANSMISSION FLUID AND VISCOSITY GRADE —
MT 643R TRANSMISSIONS
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.7.1 Fluid And Filter Changes. If using gold series filters,
change the main filter after the first 8000 km (5000 miles)
then follow the recommended fluid and filter change
intervals found in Table 2–6, and Table 2–7.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.4.4 Electronic Check Procedure.
1. For a pushbutton selector, simultaneously press the ↑ (Upshift) and
↓ (Downshift) arrows once.
2. On the lever shift selector, press the DISPLAY MODE/DIAGNOSTIC
(DMD) button once.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.4.5 Fluid Level Display Criteria. As soon as fluid level information is
requested, the Transmission Control Module (TCM) checks to see if the
conditions are right to allow display. Certain operating conditions must
be met for a period of two minutes before fluid level is displayed. The
display flashes and an 8, 7,....1 countdown occurs. Fluid level
information displays after the countdown if the following conditions have
been met:
• Engine at idle
• Sump fluid temperature at 40–104°C (104–219°F)
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
2.4.5 Fluid Level Display Criteria.
• Transmission output shaft stopped.
• Transmission in N (Neutral).
• OLS functioning properly.
Shift selector displays fluid level information two characters at a time as
shown in Table 2–1.
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
Preventive Maintenance Support:
Dipstick Calibrations / Fluid Levels
Exit Fluid Level Mode as follows:
• Pushbutton shift selector—press the N (Neutral) button
once.
• Lever shift selector—press the MODE button once or
move the lever.
Preventive Maintenance Support:
Dipstick Calibrations
Preventive Maintenance Support:
Dipstick Calibrations
Preventive Maintenance Support:
2.9 TRANSMISSION FLUID AND FILTER CHANGE PROCEDURE
2.9.1 Drain Fluid.
NOTE: Do not drain the transmission if replacing only the filters.
WARNING: Avoid contact with hot fluid or the sump when draining transmission fluid.
Direct contact with hot fluid or the hot sump may result in bodily injury.
1. Drain the fluid when the transmission is at normal operating sump temperature:
71°C–93°C (160°F–200°F). Hot fluid flows quicker and drains more completely.
2. Remove the drain plug from the oil pan and allow the fluid to drain into a
suitable container.
3. Examine the fluid for contamination.
Preventive Maintenance Support:
Filter Replacement
1. Remove twelve bolts (1), two filter covers (2), two gaskets (3), two Orings
(4), two O-rings (5), and two filters (6) from the bottom of the control
module.
2. When reinstalling parts, lubricate and install new O-rings (4) and (5) on
each cover. Lubricate O-ring inside filter 6 and push filter onto each cover
(2). Install new gaskets (3) on each cover (2) and align bolt holes in gasket
with holes in cover.
3. Install filter cover assemblies into the filter compartments. Align each
filter/cover assembly with the holes in the bottom of the control module.
Push the cover assemblies in by hand to seat the seals.
Preventive Maintenance Support:
Filter Replacement
CAUTION: Do not use the bolts to draw the filter covers to the control
module. Do not use an impact wrench to tighten the bolts. Using an impact
wrench to tighten the bolts may cause stripped threads and expensive parts
replacement. Use a torque wrench to tighten the bolts.
4. Install six bolts into each cover assembly and tighten to 51–61 N∙m
(38–45 lb ft).
5. Replace the drain plug Oring. Install the drain plug and tighten to 25–32
N∙m (18–25 lb ft).
6. Refill Transmission.
Preventive Maintenance Support:
Filter Replacement
Preventive Maintenance Support:
External Linkage adjustments
Preventive Maintenance Support:
External Linkage adjustments
CONNECTING SHIFT SELECTOR CONTROL
Proper shift selector adjustment is critical. Improper linkage adjustment can
cause metering of clutch apply fluid, resulting in clutch slippage. The position of
the selector lever (refer to Figure 6–6) directly affects the position of the
selector valve. When the adjustment is correctly made, the linkage to the
selector lever retainer pin should move freely. When there is no free pin
movement, it is recommended that the linkage be adjusted as follows:
1. At the driver’s position, place shift lever in the R (Reverse) position.
2. At the transmission, rotate the selector lever to the R (Reverse)
position.
3. Align the linkage connector pin to the selector lever. Adjust the linkage if
necessary to obtain a free pin.
4. Do the same procedure again, except this time begin with the driver’s shift
selector in the first position.
Preventive Maintenance Support:
External Linkage adjustments
CONNECTING SHIFT SELECTOR CONTROL
1. At the driver’s position, place shift lever in the R (Reverse) position.
2. At the transmission, rotate the selector lever to the R (Reverse)
position.
3. Align the linkage connector pin to the selector lever. Adjust the linkage if
necessary to obtain a free pin.
4. Do the same procedure again, except this time begin with the driver’s shift
selector in the first position.
5. Start the engine and move the shift selector to D (Drive). Slowly move the
shift selector toward N (Neutral). Clutch release or engine rpm increase should
be felt before the lever reaches the N (Neutral) slot.
6. Move the lever to the R (Reverse) position; then slowly move the shift
selector toward N (Neutral). Clutch release or an engine rpm increase should be
felt before the selector reaches the N (Neutral) slot.
Preventive Maintenance Support:
External Linkage adjustments
Preventive Maintenance Support:
External Linkage adjustments
Preventive Maintenance Support:
Identification of shift Selectors
Preventive Maintenance Support:
Identification of shift Selectors
Preventive Maintenance Support:
Identification of shift Selectors
Manual selector shaft and retaining nut.
INSTALLING SHIFT SELECTOR LEVER
CAUTION: Manual selector shafts that are center drilled at their outer ends require
an M10 x 1.5-6G nut (metric thread). Shafts that are undrilled require a 3⁄8-16 nut
(standard inch series). Use of the wrong nut will damage both the shaft and nut.
Torque for either nut is 15–20 lb ft (20–27 N·m). Excessive torque applied to the nut
without holding the lever can damage the internal lever. Do not use an impact wrench.
Manual selector shaft and retaining nut.
INSTALLING SHIFT SELECTOR LEVER
• Install the selector lever onto the selector shaft. The flats in the lever slot interfere
slightly with the tapered flats on the selector shaft before the lever seats against the
shaft shoulder. If such an interference fit is not present, replace the selector lever.
• Install the lever retaining nut, finger tight, against the lever.
Manual selector shaft and retaining nut.
INSTALLING SHIFT SELECTOR LEVER
• Shift the selector shaft to a position away from either end position. Two detent
“clicks” from either end position is recommended.
• Hold the lever and tighten the nut to 15–20 lb ft (20–27 N·m) (Figure 3–2).
The lever must be seated fully against the shaft shoulder.
Preventive Maintenance Support:
Driveline Inspection
Inspect the chassis and driveline components for the following
conditions, and
correct them as appropriate:
• Transmission mounts—broken or worn-out
• Bolts and other hardware—damaged, missing, or incorrect
• Isolators (rubber mounts)—damaged or missing
• Driveline angles—run-out, or balance which does not conform to the
manufacturer’s recommendations
• Driveline yoke slip joints:
– freedom of movement
– damaged or worn-out
– correctly lubricated
– correctly indexed
Preventive Maintenance Support:
Driveline Inspection
•
•
–
–
–
–
•
•
Driveline midship or hanger bearings—damaged or misaligned
Universal joints:
freedom of movement
damaged or worn-out
correctly lubricated
correctly indexed
Vehicle differential backlash—manufacturer’s specification
Universal joint coupling—alignment and differential damage
Preventive Maintenance Support:
Driveline Inspection
• Cross-frame members and rear support members—condition and
location
• Auxiliary transmission:
– shaft alignment
– alignment of yoke or flange
– backlash
– fluid leaks
Preventive Maintenance Support:
Driveline and output Flanges
2–2. INSPECT DRIVELINE COMPONENTS
a. General Inspection of the Driveline.
• Look for an uneven buildup of paint, undercoating, or mud.
• Inspect for missing shaft balance weights (refer to Figure 2–2).
• Inspect the transmission yoke or flange bolts to be sure they are tight.
• Inspect the engine and transmission mounts to be sure the engine/transmission
power package is
still at the proper angle.
Preventive Maintenance Support:
Driveline and output Flanges
Preventive Maintenance Support:
Driveline and output Flanges
b. Inspect Driveline Intermediate Support Bearings. Inspect
the intermediate support bearings to be sure they are not
damaged and will not allow the shaft to
travel in an elliptical pattern (refer to Figure 2–3).
Preventive Maintenance Support:
Driveline and output Flanges
Preventive Maintenance Support:
Driveline and output Flanges
c. Inspect Driveline Slip Joint. Inspect the driveline
slip joint to make sure that it can move freely and
has the proper amount of travel (refer to Figure 2–4).
Preventive Maintenance Support:
Driveline and output Flanges
Driveline and output Flanges
Preventive Maintenance Support:
Driveline and output Flanges
f. Transmission Output. Inspect transmission output flange or yoke bolts
for
looseness.
g. Axle Yoke/Flange. Inspect axle pinion yoke or flange retaining
hardware for looseness.
h. Inspect Shaft Runout. Inspect the shaft runout or position of the shaft
around its operating centerline. Visually inspect the shafts for dents or
anything that might be out of position (refer to Figure 2–8).
Preventive Maintenance Support:
Driveline and output Flanges
Preventive Maintenance Support:
Driveline and output Flanges
PHASING DEFINITION
A driveline is intended to have a constant speed input and a constant speed output
with fluctuating speeds in the center sections of the driveline. Therefore, it is an
inherent design condition that causes each universal joint to speed-up and
slow-down twice during each revolution of the shaft. If the yokes on each of the
driveline elements are not in phase or parallel (refer to Figure 3–1) with each other,
the result is a fluctuation in the output speed of the driveline. This can result in
driveline vibration. At times, a vehicle manufacturer will intentionally misphase
driveshaft's. When phasing is in question, contact the vehicle manufacturer for
determination of proper phasing.
However, even if the yokes are in-phase, the angles of each universal joint must
be within a specified tolerance for a given, maximum speed. If they are not, a
vibration that can damage the transmission, driveline, and axle can be produced.
Preventive Maintenance Support:
Driveline and output Flanges (PHASING)
Preventive Maintenance Support:
Driveline and output Flanges (Angularity)
OPERATING ANGLE DEFINITION
The operating angle of a universal joint is the angle of one universal joint yoke or
shaft in relation to the other yoke or shaft.
Imagine two lines perpendicular to each yoke (refer to Figure 4–1). The angle
formed where the two lines intersect is the operating angle of the universal joint.
Preventive Maintenance Support:
Driveline and output Flanges (Angularity)
Preventive Maintenance Support:
Driveline and output Flanges (Angularity)
INSTALLED ANGLE DEFINITION
The installed angle of a driveline is the angle at which each driveline element is
installed. Refer to Figure 4–2. The installed angle of each driveline element is
used to determine the operating angle of each universal joint.
SINGLE VERSES COMPOUND ANGLES
Single operating angles exist when there is no horizontal offset of the driveline
between the transmission and axle.
Preventive Maintenance Support:
Driveline and output Flanges
REMOVING OUTPUT FLANGE OR YOKE
If replacing the transmission, you may need to transfer the output flange
or yoke to the replacement transmission. Before December 1, 1998,
output flanges or yokes were retained by two M10 x 1.5 x 30 bolts. Output
flanges or yokes are now retained by one M14 x 2.0 x 70 bolt. For the 3000
Product Family, the
one-bolt design began at S/N 6510184819. For the 4000 Product Family,
the one-bolt design began at S/N 6610038064. All 4000 Product Family use
the
one-bolt design.
Preventive Maintenance Support:
Driveline and output Flanges
REMOVING OUTPUT FLANGE OR YOKE
CAUTION: The use of an impact wrench requires a means to hold the
flange. Failure to hold the flange can cause internal damage to the
transmission.
Preventive Maintenance Support:
Driveline and output Flanges
REMOVING OUTPUT FLANGE OR YOKE
When replacing the transmission, it may be necessary to transfer input and output
flanges or yokes to the replacement transmission. If the flanges or yokes are
retained by a large self-locking nut, follow these specific procedures to remove
the nut:
1. Before removing the self-locking nut, determine if there are any notches cut
into the wrenching flats. If there are five notches, remove the nut and
discard.
2. If there are less than five notches or none at all, remove dirt and burrs from the
shaft threads. Loosen the nut until there is about 1/16 inch gap
between the nut and flange.
Preventive Maintenance Support:
Driveline and output Flanges
REMOVING OUTPUT FLANGE OR YOKE
3. Determine the running torque as the nut is being removed. The first
time the nut is removed (no notches), running torque must be at least 400
lb in. (45 N·m). Each additional time the nut is removed (one to four
notches), running torque must be at least 300 lb in. (34 N·m). Discard the
nut if it does not meet the running torque limit.
Preventive Maintenance Support:
Driveline and output Flanges
INSTALLING OUTPUT FLANGE OR YOKE
4.2.1 Output Oil Seal. Check the output oil seal for leaks or damage. Refer to
the latest edition of the approved Service Manual for replacement instructions. If
not replacing the oil seal, lubricate it with high temperature grease or
transmission fluid.
CAUTION: DO NOT attempt to polish the oil seal contact surface on the
flange or yoke. Scratches or machine type lead can cause the
seal to leak.
Preventive Maintenance Support:
Driveline and output Flanges
4.2.2 Check Flange or Yoke.
Check each flange or yoke for damage or wear.
The oil seal contact surface must be smooth and regular to prevent oil leaking past
the seal. Rotate the flange or yoke after installation to check for binding.
4.2.3 Install Output Flange or Yoke.
1. Install flange or yoke onto output shaft. Install the large O-ring on the retainer
plug. Install the bolt into the bolt hole in the plug. Install a small O-ring over the
threads of the bolt so that the O-ring seats against the retainer plug. Install
retainer plug and bolts into the flange or yoke.
2. Tighten bolt to 70–80 N∙m (52–59 lb ft).
Preventive Maintenance Support:
Periodic Inspection and Care
Transmission Inspection. Clean and inspect the exterior of the transmission at
regular intervals. Severity of service and operating conditions determine the
frequency of these inspections. Inspect the transmission for:
• Loose bolts—transmission and mounting components.
• Fluid leaks—repair immediately.
• Loose, dirty, or improperly adjusted throttle sensor.
• Damaged or loose hoses.
• Worn, frayed, or improperly routed electrical harnesses.
Preventive Maintenance Support:
Periodic Inspection and Care
Transmission Inspection.
• Worn or damaged electrical connectors.
• Dented, worn or out of phase driveline U-joints and slip fittings.
• Clogged or dirty breather (vent assembly).
• Check transmission fluid for evidence of engine coolant.
Vehicle Inspection.
Check the vehicle cooling system occasionally for evidence of transmission
fluid which indicates a faulty oil cooler.
Preventive Maintenance Support:
Periodic Inspection and Care
PREVENT MAJOR PROBLEMS
You can help keep minor problems from becoming major problems by contacting an
Allison Transmission distributor or dealer when one of these conditions occur:
• Shifting feels odd.
• Transmission leaks fluid.
• Unusual transmission-related sounds (changes in sound caused by normal engine
thermostatic fan cycling, while climbing a long grade with a heavy load, have been
mistaken for transmission-related sounds).
• CHECK TRANS light comes on frequently. CARE AND MAINTENANCE
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
ENGINE, TRANSMISSION ADAPTATION REQUIREMENTS
You must make sure a new transmission installation can be adapted to the
vehicle’s engine. Use the measurements described in this section to make
sure correct transmission to engine adaptation. Refer to Figure 5–1 or
Figure 5–2 and/or AS67–020. Typical arrangement of adaptation components
is shown in Figure 5–3.
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
Flywheel Housing Pilot Bore Diameter. The flywheel housing pilot
bore diameter must measure.
• 3000 Product Family—447.68–447.81 mm (17.625–17.630 inches)
• 4000 Product Family—511.18–511.30 mm (20.125–20.130 inches)
Flywheel Housing Bore Runout. Flywheel housing bore runout
cannot exceed 0.51 mm (0.020 inch) TIR.
Flywheel Housing Face Squareness. The flywheel housing face
cannot be out-of-square
more than 0.51 mm (0.020 inch) TIR
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
Crankshaft Hub Pilot or Adapter Diameter. The crankshaft hub
pilot or hub adapter pilot diameter must measure between 50.94–50.99 mm
(2.006–2.008 inch).
Crankshaft Hub Pilot or Adapter Squareness. The crankshaft hub or
hub adapter cannot be out-of-square more than 0.13 mm (0.005 inch) TIR.
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
Crankshaft Hub Pilot or Adapter Concentricity. The crankshaft hub
pilot or the hub adapter pilot concentricity cannot exceed 0.13 mm (0.005
inch) TIR.
Flexplate Bolt Hole Flatness. Flexplate flatness in the area of the
bolt holes is not a measurement required for the 3000 and 4000 Product
Family transmissions.
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
Torque Converter Axial Location. Using a depth gauge, measure
from the face of the torque converter housing to the torque
converter flexplate adapter mounting face (refer to Figure 5–4).
The torque converter axial location should measure:
• 3000 Product Family—49.36–50.38 mm (1.943–1.983 inch)
• 4000 Product Family—44.0–46.8 mm (1.732–1.842 inch)
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
CHECKING FLEXPLATE DRIVE ASSEMBLY
Flexplate Inspection. Check the flexplate for cracks, distortion, or
elongated bolt holes. Replace a worn or damaged flexplate.
Engine Crankshaft End Play. Make sure engine crankshaft end play
is within the engine manufacturer’s specifications.
NOTE: When assembling the flexplate to the crankshaft hub or hub
adapter, make sure the outer flexplate bolt holes are aligned.
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
CHASSIS AND DRIVELINE INSPECTION
Inspect the chassis and driveline components for the following conditions, and
correct them as appropriate:
• Transmission mounts—broken or worn-out
• Bolts and other hardware—damaged, missing, or incorrect
• Isolators (rubber mounts)—damaged or missing
• Driveline angles—runout, or balance which does not conform to the
manufacturer’s recommendations
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
• Driveline yoke slip joints:
– freedom of movement
– damaged or worn-out
– correctly lubricated
– correctly indexed
• Driveline midship or hanger bearings—damaged or misaligned
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
• Universal joints:
– freedom of movement
– damaged or worn-out
– correctly lubricated
– correctly indexed
• Vehicle differential backlash—manufacturer’s specification
• Universal joint coupling—alignment and differential damage
• Crossframe members and rear support members—condition and location
Preventive Maintenance Support:
PREPARING VEHICLE FOR TRANSMISSION INSTALLATION
• Auxiliary transmission:
– shaft alignment
– alignment of yoke or flange
– backlash
– fluid leaks
Preventive Maintenance Support:
NFPA 1911 PM Inspections
Inspections and Maintenance.
4.5.1 The fire apparatus shall meet all federal, state or provincial, and local laws
for motor vehicle inspection.
4.5.2* All inspections and maintenance shall be conducted in accordance with the
manufacturer’s recommended procedures.
4.5.3* It shall be the responsibility of the AHJ to develop and implement a
schedule for the operational checking, inspection, diagnostic checking, and
maintenance of the fire apparatus and its systems and components in accordance
with this document, the manufacturer’s recommendations, local experience,
and operating conditions.
Inspections and Maintenance. (NFPA 1911)
4.5.4 An operational check and visual check of the fire apparatus shall be
performed on a daily/weekly basis to ensure the operational readiness of the unit.
4.5.4.1
Defined systems of the apparatus shall be checked, including the fire
pump, aerial
device, warning lights, audible warning devices, cab and pump panel
instrumentation, seat belts, tires, engine, transmission, drivetrain, and brake
system.
4.5.4.2
An inspection form shall be utilized to record the
results of the operational and visual check.
Inspections and Maintenance. (NFPA 1911)
4.5.5* A complete inspection and diagnostic check of the fire
apparatus shall be conducted at least as frequently as recommended by the
apparatus manufacturer or once per year, whichever comes first.
4.5.6 Component inspections shall be performed at least as frequently as
recommended by the manufacturer and when the fire apparatus or any component
is suspected or reported to have defects or deficiencies.
4.5.7
All deficiencies found during an inspection shall be repaired or corrected by
a qualified person.
Preventive Maintenance Support:
NFPA 1911 Out Of Service Criteria
6.1.1 It shall be the responsibility of the AHJ to take the apparatus or the
defective portion of the apparatus out of service if any of the deficiencies defined
in this chapter are encountered.
6.1.2 Where a technician conducts an evaluation of the apparatus to determine if
the apparatus or a component should be taken out of service, the technician shall
report the findings to the AHJ in writing, with one of the following
recommendations:
Preventive Maintenance Support:
NFPA 1911 Out Of Service Criteria
(1) The apparatus shall be taken out of service.
(2) The apparatus shall be retained in service with specified
limitations.
(3) The apparatus shall be retained in service without limitations.
Preventive Maintenance Support:
NFPA 1911 Out Of Service Criteria
Transmission and Clutch.
6.6.1 The following defects and deficiencies of the transmission and clutch
shall cause the apparatus to be taken out of service:
(1) Automatic transmission that overheats in any range
(2) Automatic transmission that has a “do not shift” light on
(3) Transmission components that have Class 3 leakage of transmission oil
Preventive Maintenance Support:
NFPA 1911 Out Of Service Criteria
Transmission and Clutch.
6.6.2 If there are deficiencies of the following systems or components, a qualified
technician shall conduct an out-of-service evaluation and make a written
report, including recommendations to the AHJ:
(1) Clutch components
(2) Transmission components
(3) Shift linkages
Preventive Maintenance Support:
NFPA 1911 Service Recommendations
Transmission.
7.9.1 The transmission shall be inspected for security of
mounting, structural integrity, and leakage and shall be diagnostically checked.
7.9.2 The clutch and linkage, if the fire apparatus is so
equipped, shall be inspected for condition and adjustment, diagnostically
checked, and maintained in accordance with the manufacturer’s
recommendations.
Preventive Maintenance Support:
NFPA 1911 Service Recommendations
Transmission.
7.9.3 Transmission lubricants and filters shall be inspected for contamination,
and lubricants shall be maintained at the level specified by the manufacturer.
7.9.4 The lubricant and filters shall be serviced in accordance with the
transmission manufacturer’s severe service recommendation. If no severe service
recommendation exists, the shortest interval recommended by the transmission
manufacturer, based on time or mileage, shall be followed.
Preventive Maintenance Support:
NFPA 1911 Service Recommendations
Transmission.
7.9.5 The transmission controls and shift linkage shall be inspected for condition
and maintained in accordance with the manufacturer’s recommendations.
7.9.6 All transmission indicators and gauges shall be tested for proper operation
and accuracy.
7.9.7 The diagnostic codes for all electronically controlled transmissions shall be
reviewed for types and frequency of error codes that have been logged.
Preventive Maintenance Support:
NFPA 1911 Service Recommendations
Transmission.
7.9.8 Power takeoffs (PTOs) shall be inspected for security of mounting and
leakage and shall be diagnostically checked.
7.9.9 The lockup system for pumps and other accessories shall be inspected for
leakage and shall be diagnostically checked.
Preventive Maintenance Support:
NFPA 1911 Service Recommendations
Transmission.
7.9.10 Transmission braking systems shall be maintained in accordance with
the manufacturer’s recommendations.
7.9.11 Auxiliary heat exchangers installed in the transmission cooling system
shall be inspected for security of mounting, deformation, and leaks.
Troubleshooting Procedures: Drivelines
Troubleshooting Procedures: Drivelines
a. Engine Test (rpm). This test is performed with the vehicle stationary,
parking brake set, and transmission in neutral.
Start the engine and gradually increase engine rpm.
If abnormal vibration occurs, the problem could be misfire, engine and/or
torque converter out of balance, powertrain mounting problems or engine
resonance.
Troubleshooting Procedures: Drivelines
b. Powertrain Test (Road Speed). Drive vehicle along a smooth road in a
high range (4th or higher). Is vibration engine speed or road speed
related?
Determine if vibration is impacted by the amount of engine load. If
vibration increases with an increase in the amount of throttle and engine
rpm, the problem could be engine misfire or powertrain mounting system
problems.
Troubleshooting Procedures: Drivelines
c. Driveline Test (Coast).
WARNING: The Driveline Test is a troubleshooting procedure only and
should not be done during normal vehicle operation. This test cannot be
performed on public highways and must be performed on flat, level
ground.
The Driveline Test will reveal vibrations caused by the driveline.
Driveline vibrations usually show up within a specific speed range.
Troubleshooting Procedures: Drivelines
c. Driveline Test (Coast).
To perform a Driveline Test, in an high range (4th or higher) accelerate
past the speed range where the vibration occurs, shift into N (Neutral)
and coast back through the vibration range.
If the vibration is still evident and frequency decays with decreasing
speed, the potential cause is probably driveline oriented.
Troubleshooting Procedures:
Shift Complaints
DIAGNOSIS
Poor performance may activate a code without illuminating the CHECK TRANS
light. Continued illumination of the CHECK TRANS light during vehicle
operation (not start-up) indicates the ECU has signaled a diagnostic code. Up to
five diagnostic codes may be recorded. Diagnostic codes may be read and
cancelled by using the Allison DOC™ diagnostic tool or shift selectors (refer to
Figure 11).
Troubleshooting Procedures:
Shift Complaints
Troubleshooting Procedures:
Shift Complaints Lockup Operations
LOCKUP OPERATION
Fluid coupling can transfer a large amount of torque from converter pump to the
turbine. However, the converter turbine can never quite reach pump speed due
to kinetic energy losses. The lockup clutch provides a direct drive from the
engine to the transmission gearing, enabling kinetic energy losses to be
overcome.
Troubleshooting Procedures:
Shift Complaints Lockup Operations
The lockup clutch consists of three elements:
• The piston—driven by the engine
• Clutch plate/damper—located between the piston and the backplate and
splined to the converter turbine
• Backplate—driven by the engine
The lockup clutch engages in response to electronic signals from the TCM. As
turbine speed
approaches engine speed (after second range has been attained), the TCM
energizes the TCC lockup
solenoid in the control module. This energized lockup solenoid causes a solenoid
regulator valve to
open directing the transmission’s hydraulic main pressure to the cavity
behind the lockup clutch piston.
Troubleshooting Procedures:
Shift Complaints Lockup Operations
LOCKUP OPERATION
Hydraulic main pressure causes the piston to move against the clutch plate,
pressing it against the backplate.
The integral damper is a spring, shock-absorbing component that is assembled as
a part of the lockup clutch plate. It reduces vibration and torsional forces from
the engine and transmission when the lockup clutch is engaged.
The converter pump, turbine, and turbine shaft all
rotate at exactly the same speed as the engine, with the lockup clutch engaged.
This mechanical direct-drive lockup clutch eliminates converter slippage and
allows maximum fuel economy.
The TCM disengages the lockup clutch if a critical transmission malfunction
occurs. This eliminates the mechanical connection between the transmission
power train and the engine. The converter returns to a fluid coupling drive
when the lockup clutch is disengaged.
Troubleshooting Procedures:
Shift Complaints Lockup Pressure
To attain lockup, pressurized fluid must flow to the lockup piston. The
lockup solenoid regulator valve in the control module directs fluid
pressure to the lockup clutch piston. Movement of the solenoid
regulator valve allows regulated main pressure to be delivered to the
lockup piston and engage the clutch. If a critical transmission
malfunction or electrical interruption occurs, the TCM disengages the
lockup clutch.
Troubleshooting Procedures:
PTO Installations
• The prescribed backlash between the drive gear (in transmission) and driven
gear (in PTO) is 0.006–0.029 inch (0.15–0.73 mm) or as specified by the PTO
manufacturer.
• Early model transmissions have a 6/8 pitch drive gear while later models have a
6 pitch gear. A 6 pitch or a 6/8 pitch PTO may be used with either gear, but the
backlash must be maintained.
• If the PTO has a manual disconnect, ensure that the disconnect lever is in the
disconnect position before installation. The PTO must be installed on the mounting
pad with its driven gear to the rear of the PTO drive gear in the transmission.
Troubleshooting Procedures:
PTO Installations
• Determining PTO Backlash — PTO not installed: backlash can be measured
with special tool J 34814 (Figure 3–3). Reference SIL 50-TR-83 and Service
Manuals SM1317EN and SM1546EN (latest revisions).
— PTO installed: measure through the inspection port (if provided) with a
dial indicator. On PTO units with no inspection port, rotate the PTO shaft back
and forth. Rattling gears indicate too much backlash and require the removal of
one or more gaskets from beneath the PTO housing. Difficult engagement or
whining gears indicate a tight fit and require the addition of one or more
gaskets.
Troubleshooting Procedures:
PTO Installations
• Install the PTO unit and gasket(s) flush to the mounting pad; do not force.
Avoid bumping the snapring (Figure 3–4), which could be displaced. Secure
the PTO with six mounting bolts; tighten to 26–32 lb ft (35–43 N·m).
NOTE: Do not remove all gaskets from beneath the PTO housing. One gasket
(minimum) is required to prevent fluid leakage.
Troubleshooting Procedures:
PTO Installations J34814 Backlash tool
Troubleshooting Procedures:
PTO Installations Backlash
Troubleshooting Procedures:
PTO Installations
• On PTO assemblies that require pressure lubrication, install the lubrication
tube and fittings. The lubricating fluid comes from the line returning to the
transmission from the cooler. Fluid should be directed to the PTO lubrication
circuit after passing through a 0.032 inch (0.81 mm) restriction. (Usually, the
restriction is already located in the PTO.)
Troubleshooting Procedures:
PTO Installations Backlash
Troubleshooting Procedures:
PTO Installations External Identifications
Troubleshooting Procedures:
PTO Installations Pressure Port Locations EV 3000/3500
Troubleshooting Procedures:
PTO Installations Pressure Port Locations EV 3000/3500
Troubleshooting Procedures:
PTO Installations Pressure Port Locations EV 4000/4500
Signal Port
Locations
Troubleshooting Procedures:
PTO Installations Pressure Port Locations EV 4000/4500
Troubleshooting Procedures:
PTO Installations Pressure Port Locations 1000/2000
Product Family
Troubleshooting Procedures:
PTO Installations 1000/2000 Product Family
Troubleshooting Procedures:
PTO Pressure Installations 1000/2000 Product Family
Troubleshooting Procedures: Fluid Checks
IMPORTANCE OF PROPER TRANSMISSION FLUID LEVEL
Transmission fluid cools, lubricates, and transmits hydraulic power. Always
maintain proper fluid level. If fluid level is too low, the torque converter and
clutches do not receive an adequate supply of fluid and the transmission
overheats. If the level is too high, the fluid aerates—causing the transmission
to shift erratically and overheat. Fluid may be expelled through the breather
or dipstick tube when the fluid level is too high.
Troubleshooting Procedures: Fluid Checks
IMPORTANCE OF PROPER TRANSMISSION FLUID LEVEL
• Aeration changes the viscosity and color of the transmission fluid to a thin
milky liquid and adversely affects transmission performance. The primary
causes of aeration are improper fluid, not enough fluid in the sump, too
much fluid in the sump, or a defective or missing seal-ring on the intake
pipe of the internal filter. A low fluid level will not completely cover the
internal filter. Therefore, fluid and air are drawn into the system by the
input pump and are directed to the control circuits and converter causing
cavitational noises.
Troubleshooting Procedures: Fluid Checks
TRANSMISSION FLUID CONTAMINATION
2.8.1 Fluid Examination. At each fluid change, examine the drained fluid for
evidence of dirt or water. A normal amount of condensation (not to exceed 0.2
percent) will appear in the fluid during operation.
2.8.2 Water. Obvious water contamination of the transmission fluid or transmission
fluid in the cooler water (in heat exchanger) indicates a leak between the water and
fluid areas of the cooler. Inspect and pressure test the cooler to confirm the leak.
Replace leaking coolers.
Troubleshooting Procedures: Fluid Checks
TRANSMISSION FLUID CONTAMINATION
2.8.3 Engine Coolant. CAUTION: Engine coolant in the transmission hydraulic
system requires immediate action to prevent malfunction and possible serious
transmission damage. Completely disassemble, inspect, and clean the
transmission. Remove all traces of the coolant and varnish deposits resulting from
engine coolant contamination (ethylene glycol).
Troubleshooting Procedures: Fluid Checks
TRANSMISSION FLUID CONTAMINATION
2.8.4 Metal. Metal particles in the fluid (except for the minute particles
normally trapped in the oil filter) indicate internal transmission damage. If these
particles are found in the sump, the transmission must be disassembled and
closely inspected to find their source. Metal contamination requires complete
transmission disassembly. Clean all internal and external hydraulic circuits, cooler,
and all other areas where the particles could lodge.
Troubleshooting Procedures: Fluid Checks
b. Abnormal Conditions. Transmission fluid must be changed whenever there
is evidence of dirt or high temperature. A high temperature condition is
indicated by transmission fluid:
• Discoloration
• Strong odor
• Fluid analysis.
Troubleshooting Procedures: Fluid Checks, Breather
BREATHER
a. Location and Purpose. The breather is located on top of the transmission
converter housing. The breather prevents air pressure build-up within the
transmission and its passage must be kept clean and open.
b. Maintenance.
CAUTION: DO NOT SPRAY STEAM, WATER, OR CLEANING SOLUTION DIRECTLY AT
THE BREATHER. Spraying steam, water, or cleaning solution at the breather can
force water or cleaning solution into the transmission and contaminate the
transmission fluid. Seal all openings and vent assembly (breather) before spraying
steam, water, or cleaning solution on the transmission.
The amount of dust and dirt encountered will determine the frequency of breather
cleaning. Use care when cleaning the transmission.
Troubleshooting Procedures: Fluid Checks, Breather
BREATHER
c. Replacement. Always use the correct wrench sized to remove or replace the
breather. Using pliers or a pipe wrench can crush or damage the breather stem and
produce metal
particles which could enter the transmission. Tighten the breather to
12–16 N•m (9–12 lb ft).
Troubleshooting Procedures: Fluid Leak Diagnostics
FLUID LEAK DIAGNOSIS
2.10.1 Finding the Leak.
1. Identify the fluid. Determine whether the fluid is engine oil, automatic
transmission fluid, or hydraulic fluid from a particular vehicle system.
2. Operate the vehicle to reach normal operating temperature and park the
vehicle. Inspect the vehicle to identify the source of the leak. Refer to the
following list for possible points of transmission fluid leaks and their causes.
Troubleshooting Procedures: Fluid Leak Diagnostics
FLUID LEAK DIAGNOSIS
• Transmission mating surfaces:
– Attaching bolts not correctly aligned
– Improperly installed or damaged gasket
– Mating surface(s) damaged
Troubleshooting Procedures: Fluid Leak Diagnostics
FLUID LEAK DIAGNOSIS
• Housing leak:
– Fill tube or plug seal damaged or missing
– Fill tube bracket dislocated
– Oil cooler connector fittings loose or damaged
– Output shaft seals worn-out or damaged
– Pressure port plugs loose
– Porous casting
Troubleshooting Procedures: Fluid Leak Diagnostics
FLUID LEAK DIAGNOSIS
• Leak at converter end:
– Converter seal damaged
– Seal lip cut—check converter hub for damage
– Garter spring missing from seal
– Converter leak in weld area or O-ring seal
– Porous casting
Troubleshooting Procedures: Fluid Leak Diagnostics
FLUID LEAK DIAGNOSIS
• Fluid comes out of fill tube:
– Overfilled—incorrect dipstick
– Plugged vent
– Water or coolant in fluid—fluid appears milky
– Incorrect electronic fluid indication
– Drain-back holes plugged
Troubleshooting Procedures: Fluid Leak Diagnostics
FLUID LEAK DIAGNOSIS
3. Visually inspect the suspected area. Inspect all gasket mating surface
for leaks.
4. If the leak still cannot be identified, clean the suspected area with a degreaser,
steam, or
spray solvent. Clean and dry the area. Operate the vehicle for several miles at
varying speeds.
Inspect the vehicle for leaks. If the leak source still cannot be identified, use the
powder
method, and/or the black light and dye method as explained below.
Troubleshooting Procedures: Fluid Leak Diagnostics
FLUID LEAK DIAGNOSIS
Powder Method.
1. Clean the suspected area.
2. Apply an aerosol-type white powder to the suspected area.
3. Operate the vehicle under normal operating conditions.
4. Visually inspect the suspected area and trace the leak path over the white
powder.
Troubleshooting Procedures: Fluid Leak Diagnostics
FLUID LEAK DIAGNOSIS
Black Light and Dye Method. A dye and black light kit for finding
leaks is available. Refer to the manufacturer’s directions when using the kit. Refer
to the kit directions for the color of the fluid/dye mix.
1. Pour the specified amount of dye into the transmission fill tube.
2. Operate the vehicle under normal operating conditions.
3. Direct the black light toward the area suspected of leaking. Dyed fluid
will appear as a brightly colored path leading to the leak.
Troubleshooting Procedures:
NFPA 1911 Leak Classifications
Leak: The escape of a fluid or gas from a hose, pipe, coupling, connection, or
other confining structure at any point where the escape should not occur.
Class 1 Liquid Leakage: Seepage of liquid, as indicated by wetness or
discoloration, not great enough to form drops.
Class 2 Liquid Leakage: Leakage of liquid great enough to form drops, but
not enough to cause drops to fall from the item being inspected.
Class 3 Leakage: Leakage of liquid great enough to cause drops to fall from
the item being inspected.
Troubleshooting Procedures:
Stall Test
Purpose. Stall testing is performed to determine if a vehicle performance
complaint is due to an engine or transmission malfunction. Stall testing is a
troubleshooting procedure only—never perform a stall test as a general check or
during routine maintenance.
Transmission stall speed is the maximum engine rpm attainable when the engine is
at full throttle and the torque converter turbine is not moving, or “stalled.” After
a transmission stall test, compare the actual full throttle engine speed at torque
converter turbine stall with specifications established by the vehicle manufacturer.
Troubleshooting Procedures:
Stall Test
WARNING: To help avoid personal injury, such as burns, from hot
transmission fluid and/or to help avoid equipment damage, do not stall the torque
converter for more than ten seconds maximum and monitor transmission fluid
temperature. Immediately return the engine to idle if converter out (to cooler)
temperature exceeds 150°C (300°F). Operating the transmission at high engine
power at transmission stall or near stall conditions causes a rapid rise in the
transmission fluid temperature. The fluid in the transmission torque converter is
absorbing all of the engine power and the vehicle cooling system cannot dissipate
the excessive heat load. Extended operation under high heat load conditions causes
transmission and cooling system damage, and can possibly fail hydraulic lines
causing leaking high temperature fluid.
Troubleshooting Procedures:
Stall Test
WARNING: To help avoid personal injury and equipment damage
while conducting a transmission stall test, the vehicle must be positively
prevented from moving.
Apply the parking brake, the service brake, and chock the wheels securely. Warn
personnel to keep clear of the vehicle and its travel path.
Troubleshooting Procedures:
Diagnostic Reference Material
DIAGNOSTIC CODES OVERVIEW
Diagnostic codes are numerical indications relating to a malfunction in
transmission or vehicle operation. These codes are logged in the TCM/ECU
memory with the most severe or most recent code listed first. A maximum of five
codes (numbered d1–d5) may be listed in memory at one time. As codes are
added, the oldest non-active code is dropped from the list. If all codes are active,
the code with the lowest priority that is not included on the severity list is
dropped from the list.
Troubleshooting Procedures:
Diagnostic Reference Material
DIAGNOSTIC CODES OVERVIEW
Diagnostic codes and code information may be accessed through the pushbutton
and lever shift selectors or the Allison DOC™ For PC–Service Tool.
The TCM/ECU separately stores the active and historical (non-active) codes. An
active code is any code that is current in the TCM/ECU decision-making process.
Troubleshooting Procedures:
Diagnostic Reference Material
Troubleshooting Procedures:
Diagnostic Reference Material Shift Inhibits
SHIFT INHIBITS
The transmission control system will inhibit shifting to protect the transmission
from some types of abusive operation, in response to diagnostic trouble codes,
and to satisfy transmission feature/option requirements. These shift inhibits fall
within the following types:
• Above idle neutral to range shifts
• Forward/reverse directional shifts
• Transmission problems
• Auxiliary equipment operation
Troubleshooting Procedures:
Diagnostic Reference Material, Shift Inhibits
Above-Idle Neutral-to-Range Shifts.
Above-idle (greater than 900 rpm in Allison 4th Generation transmissions,
and greater than 1000 rpm in previous transmissions) shifts from N
(Neutral) to R (Reverse) or N (Neutral) to a forward range are normally
inhibited (except in emergency vehicles or some other type of specialized
equipment). When these shifts are inhibited, the RANGE INHIBIT(ED) light
illuminates. See the section in this manual for further information.
Troubleshooting Procedures:
Diagnostic Reference Material, Shift Inhibits
Forward/Reverse Directional Shifts.
Forward/reverse directional changes are typically not permitted if
appreciable output shaft speed is detected. When these shifts are inhibited,
the RANGE INHIBIT(ED) light illuminates.
Troubleshooting Procedures:
Diagnostic Reference Material, Shift Inhibits
Transmission Problems. Lights such as the RANGE INHIBIT(ED),
CHECK TRANS, or MIL, and a flashing PRNDL display are illuminated when the
transmission detects a functional concern.
An illuminated RANGE INHIBIT(ED) light or a flashing PRNDL display indicates the
TCM has detected a condition in which directional shifts are not allowed to be
made. This inhibited state can be a self-clearing or lasting condition depending on
the amount of time the condition is present.
The following conditions may cause an inhibited state:
• Engine speed too high
• Throttle percentage incorrect
• Output speed movement
Troubleshooting Procedures:
Diagnostic Reference Material, Shift Inhibits
Auxiliary Equipment Operation. The TCM prevents shifts from P
(Park), PB (Auto-Apply Parking Brake), or N (Neutral)-to-range when auxiliary
equipment is in operation (such as a wheelchair lift). For some vehicles,
such as buses, shifts from P (Park), PB (Auto-Apply Parking Brake), or N
(Neutral)-to-range are prevented unless the brake pedal is pressed.
Troubleshooting Procedures:
Diagnostic Reference Material Mode Indicator LED
MODE Button—The MODE button can allow the driver to enable a
secondary shift schedule, PTO enable, or other special functions that have been
programmed into the ECU unit at the request of the OEM. For example, a vehicle OEM
may have provided a secondary shift schedule for improved fuel economy. The name
of the special function (ECONOMY) appears on the MODE ID label adjacent to the MODE
button. Pressing the MODE button activates the ECONOMY shift schedule
and illuminates the MODE INDICATOR LED. When the Diagnostic Display Mode has been
entered, the MODE button is used to view and toggle through diagnostic code
information. The code displayed is active if the MODE INDICATOR LED is
illuminated.
Troubleshooting Procedures:
Diagnostic Reference Material
Troubleshooting When No Diagnostic Codes Are Present.
· Always start with the basics:
— Make sure the shifter is in the appropriate range.
— Inspect the fluid level.
— Make sure batteries are properly connected and charged.
— Make sure electrical connections are properly made.
— Inspect support equipment for proper installation and operation.
Troubleshooting Procedures:
Diagnostic Reference Material
Troubleshooting When No Diagnostic Codes Are Present.
· If the troubleshooting charts refer you to an Electronic Control test procedure,
use the diagnostic code troubleshooting information that best applies to the
situation.
· Use the transmission’s individual clutch-apply circuit pressure taps when
necessary.
Troubleshooting Procedures: Checks and Adjustments
ROAD TEST AND VEHICLE OPERATION CHECKLIST
Driveability.
Drive-away checks are performed to verify proper transmission and support
equipment installation and operation. The following steps outline drive-away check
procedures:
1. Check fluid—fill the transmission with the appropriate fluid.
2. Start the vehicle—check for proper system response during startup:
a. Turn on the vehicle’s master/ignition switch.
b. The CHECK TRANS light should come on.
c. Start the engine.
d. The CHECK TRANS light should go off.
e. N should appear in the shift selector display.
Troubleshooting Procedures: Checks and Adjustments
ROAD TEST AND VEHICLE OPERATION CHECKLIST
Driveability.
3. Clear Trouble Codes—during installation, it is common for false codes to be
stored in the electronic control’s TCM. These codes must be cleared prior to road
testing the vehicle.
4. Road Test the Vehicle—allow the electronic control time to converge shifts.
5. Check for Proper Operation—check all components for proper mounting and
operation, and check for transmission fluid leaks at gasket surfaces, lines, and hoses.
Troubleshooting Procedures: Checks and Adjustments
ROAD TEST AND VEHICLE OPERATION CHECKLIST
Driveability.
6. Recheck for Trouble Code—use the Allison DOC® For PC–Service Tool or shift
selector to determine if codes were set during the road test.
7. Troubleshoot—if codes exist after the road test, problems must be found and
corrected (refer to TS3989EN, Allison 4th Generation Controls Troubleshooting
Manual).
Troubleshooting Procedures: Checks and Adjustments
ROAD TEST AND VEHICLE OPERATION CHECKLIST
Road Test Checklist.
Complete the following checklist.
• Neutral Start Circuit:
– Starts only in N (Neutral)
• Instruments:
– CHECK TRANS light and shift selector display
– Transmission fluid pressure gauge—if used
– Speedometer
Troubleshooting Procedures: Checks and Adjustments
ROAD TEST AND VEHICLE OPERATION CHECKLIST
Road Test Checklist.
– Temperature gauge—if used
– Reverse warning system—if used
• Transmission Fluid:
– Fluid level meets specifications—cold, neutral, level
– No leaks
Troubleshooting Procedures: Checks and Adjustments
ROAD TEST AND VEHICLE OPERATION CHECKLIST
Road Test Checklist.
• No-Load Governed Engine Speed:
– No-load governed speed of engine
– Adjust governor as necessary—refer to the manufacturer’s specifications for
the engine transmission being tested.
• Output Retarder:
– Operation of the output retarder, if installed, while descending a grade or
slowing on a level road.
Troubleshooting Procedures: Checks and Adjustments
ROAD TEST AND VEHICLE OPERATION CHECKLIST
Road Test Checklist.
• PTO—if installed:
– PTO operation—Refer to the appropriate Operator’s Manual.
• Shift Sequence:
– Transmission upshifts and downshifts smoothly through all ranges
• Other Checks:
– Stall test
– Shift quality
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
Electronic Software Series:
Allison transmissions have one of three electronic control systems: WTEC III
Controls, Allison 4th Generation Controls, or Allison 4th Generation MY09
Prognostics Controls. The current electronic control system being offered is
Allison 4th Generation MY09 Prognostics Controls.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
VEHICLE INTERFACE MODULE (VIM)
The optional Vehicle Interface Module provides the necessary relays, fuses, and
connection points to interface between the TCM (Throttle Position Sensor) and the
vehicle electrical system. The VIM contains two 10-amp fuses and two to six
relays in a bolted, splashproof container. The correct voltage VIM relays
must be used and may be either 12V or 24V types. When the relay coil is a switch-
to-ground output with power supplied by the ignition, the relay must match
ignition voltage. When the relay coil is a switch-to battery output powered by the
TCM, the relay must match TCM voltage.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
VEHICLE INTERFACE MODULE (VIM)
The two 10-amp fuses in the VIM protect the main power to the TCM circuit and
the TCM to ignition circuit. The VIM relays provide switched outputs to a
specific function when actuated by the TCM. Two relays provide output to the
reverse warning and neutral start circuits and four relays are available for
special function outputs. Additional circuits from the TCM pass directly through
the VIM and provide power, battery ground, and output to the electronic
speedometer.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
THROTTLE POSITION SENSOR (TPS)
On vehicles not equipped with electronically-controlled engines, a throttle
position sensor (TPS), which is a sliding resistor sensor, is attached to the engine
fuel control linkage. An analog TPS is seldom used. However, a discussion of its
operation is provided below.
The sensor is actuated by the mechanical throttle cable that causes the contacts
of the resistor to move along the resistive strip and continuously sends the exact
throttle position to the TCM.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
THROTTLE POSITION SENSOR (TPS)
To properly communicate throttle position to the TCM, the TPS must convert its
mechanical movement to an electrical form the TCM can understand.
The TCM delivers a constant voltage to one terminal of the TPS resistive strip. The
other TPS terminal connects to ground. As the contacts slide along the resistive
strip, each position delivers a different voltage (refer to Table 1) to the TCM. The
TCM converts this voltage into percent. Each millimeter of travel converts to
approximately 0.110 volts. Figure 22 diagrams the voltage and throttle movement
relationship.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
THROTTLE POSITION SENSOR (TPS)
Throttle percent is proportional to the amount of travel of the TPS. A small amount
of travel corresponds to a low throttle percentage and a large amount of travel
corresponds to a high throttle percentage.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
THROTTLE POSITION SENSOR (TPS)
The throttle position sensor is self-calibrating within its
normal operating range. Each time the vehicle is started and the TCM is initialized,
the idle position that is stored for closed throttle is increased from its previous
lowest reading. Also, the wide open throttle position is reduced from its previous
highest reading. Once the new position is read from the TPS, the idle and wide
open throttle set points are continuously readjusted to the lowest and highest
points, respectively. This calibration enables the TCM to compensate for TPS cable
wear.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
THROTTLE POSITION SENSOR (TPS)
The TPS is not used in vehicles equipped with
electronically-controlled engines. On those vehicles, the throttle position data is
sent from the engine electronic controls directly to the transmission electronic
controls over one of the serial communication links (J1708/
1587, J1939, CAN) or via a PWM signal to the TPS input. The TCM will autodetect
the throttle signal.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
Throttle Position Sensor (TPS) Adjustment—Using Diagnostic Tool. When
properly installed by the equipment manufacturer, the TPS should not require
adjustment. Confirm that the throttle sensor has been installed to manufacturer
specification before adjusting the throttle position sensor. The idle position should
be approximately 8.9 mm or 0.97 volts or higher, and full throttle position should
be approximately 35.7 mm or 3.889 volts or lower. The TPS is self-calibrating,
meaning there is no optimum closed position or wide open position. As long as the
travel is within 8.5–35.7 mm range, the TPS is set properly. A total stroke of 15.2–
22.9 mm must be maintained.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
Electronic Controls: Basic understanding of Allison electronic
controls to include the following
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: HT-MT Do not shift lights
When programmed operating parameters have been exceeded, the ECU
automatically takes action to protect the vehicle and the transmission. If this
occurs, the CHECK TRANS light on your instrument panel, or the CHECK TRANS
light and the DO NOT SHIFT light, which is located on your shift selector, will turn
on. When the DO NOT SHIFT light comes on, a buzzer is also sounded for a
moment to tell you there is a problem. Whenever either one of these lights come
on, the transmission will respond to ensure the safest possible operation of the
vehicle.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: Status Lights
STATUS LIGHTS
Every time the engine is started, the status lights come on. They go off after a
few seconds. This momentary lighting is to show that the light bulbs are
working properly. If either status light does not come on during engine start,
immediately replace the bulb.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: Status Lights
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: Status Lights
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: Status Lights Reset Procedure
RESET PROCEDURE MT and HT Transmissions
When the status light (or lights) comes on, a reset procedure can be performed to
clear the system.
• To reset the ECU, bring the vehicle to a stop at a safe location and shut off the
engine. Wait 10 seconds and restart the engine.
• If the problem is temporary, the status light (or lights) will not come back on and
your vehicle will operate in a normal manner.
• If the problem is not temporary, the status light (or lights) will come back on and
the transmission may stay in neutral, operate in only the lower ranges, or operate
in a normal manner. The type of operation permitted by the ECU will depend on the
type of problem.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: Welding Caution
Electronic Controls: Basic understanding of Allison electronic
controls to include the following:
Allison WTEC 3 Controls Identification
Electronic Controls: Basic understanding of Allison electronic
controls to include the following:
Allison 4th Generation Controls Identification
Electronic Controls: Basic understanding of Allison electronic
controls to include the following:
Allison MY 09 4th Generation Controls Identification
Model Year ’09 4th Generation Electronic Controls Shift
Selectors
Electronic Controls: Basic understanding of Allison electronic
controls to include the following:
Prognostics Functionality My 09
Model Year ’09 prognostics monitor various operating parameters
to determine and alert you when a specific maintenance function is
required. Model Year ’09 prognostics feature Oil Life Monitor, Filter
Life Monitor and Transmission Health Monitor. At this time, Allison
Approved TES 295 transmission fluid is required to engage Model Year
’09 prognostics.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Number of stored Trouble Codes
b. Diagnostic Codes. Diagnostic codes are stored in memory. Up to
five codes, in memory positions d1 through d5, can be stored, with the
most recently stored code displayed first.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic Codes Checking Logged Diagnostic Codes
To enter the diagnostic code function:
1. Bring the vehicle to a complete stop. Apply the parking brake.
2. Using a pushbutton shift selector, simultaneously press the
UP and DOWN arrows two times. Using a lever shift selector, press the
DIAGNOSTICS button two times.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic Codes Checking Logged Diagnostic Codes
Diagnostic codes will appear two characters at a time on a pushbutton or lever
selector.
When the diagnostic function is entered, the first code (position d1) is displayed as
follows:
Example Code: P O7 22
Displayed as: d1, P, 07, 22
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic Codes Checking Logged Diagnostic Codes
The Code Position (d1) is the first item displayed, followed by the
Diagnostic Trouble Code (DTC),** P, 07, 22. Each item is displayed for about one
second. The display cycles continuously until the next code list position is accessed
by pressing the MODE button. (4th Generation Code Displayed)
Example Code: P O7 22
Displayed as: d1, P, 07, 22
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic Codes Checking Logged Diagnostic Codes
To enter the diagnostic code function:
1. Bring the vehicle to a complete stop. Apply the parking brake.
2. Using a pushbutton shift selector, simultaneously press the
UP and DOWN arrows two times. Using a lever shift selector, press the
DIAGNOSTICS button two times.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic Codes Checking Logged Diagnostic Codes
To read the digital display codes: Diagnostic codes will appear one digit at a time
on a lever or pushbutton selector.
When the diagnostic function is entered, the first code (position d1) is
displayed as follows: (WTEC 3 Codes Displayed)
Example Code: 1312
Displayed as: d1, 1, 3, 1, 2
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
When intermittently occurring codes exist, inspect, test, and correct the
following items:
· Dirty, damaged, or corroded harness connectors and terminals.
· Terminals not fully seated in connectors.
· Damaged harnesses (due to poor routing, chafing, excessive heat, tight bends,
etc.).
· Improperly mounted electronic control components.
· Poor connector seals (where applicable).
· Exposed harness wires.
· EMI generating components and accessories.
· Loose ground connections.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic codes consist of a two-digit main code and a two-digit
subcode. WTEC 3 Generation Codes
· Main codes are listed first and provide the general condition or area
of a fault detected by the ECU.
· Subcodes are listed second and provide specific areas or conditions
within the main code that caused the fault.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic codes consist of a two-digit main code and a two-digit
subcode.
· Example of Code 13 12:
— 13 indicates a problem with ECU voltage
— 12 indicates the problem is caused by low voltage
· Example of Code 32 12:
— 32 indicates a problem with the throttle position sensor signal
— 12 indicates that the throttle position sensor signal is low
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic codes consist of a two-digit main code and a two-digit
subcode.
Diagnostic codes are displayed one character or digit at a time. Table 2–11 is an
example of code 21 12. Each character or digit is displayed for about one
second.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Diagnostic codes consist of a two-digit main code and a two-digit
subcode.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
The CHECK TRANS light is usually located on the vehicle’s instrument panel.
When the light is “ON” and the shift selector display is flashing, shifts are being
inhibited by the ECU.
· This occurs when the ECU senses abnormal conditions in the transmission.
· During this time, the digit on the shift selector displays the range in which the
transmission is locked.
· The transmission may continue to operate with inhibited shifts.
· The ECU will not respond to shift selector requests.
· Direction changes and shifts to and from neutral will not occur.
· If the ignition is turned “OFF” and then “ON” while the CHECK TRANS light is
illuminated, the transmission will remain in neutral until the diagnostic code is
cleared.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
The CHECK TRANS light is usually located on the vehicle’s instrument panel.
Whenever the CHECK TRANS light is illuminated, the ECU logs a diagnostic
code in memory. The diagnostic codes can be accessed through the shift selector
display or through the Allison DOC™ service tool.
NOTE: Diagnostic codes can be logged without illuminating the CHECK TRANS light.
This occurs when the ECU senses a problem but determines that the problem will
not cause immediate transmission damage or dangerous performance.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
Mobile Radio Installation Locations (RFI)
Allison Transmission electronic control systems are designed
and manufactured to comply with all FCC and other guidelines regarding
radio frequency interference/electromagnetic interference (RFI/EMI) for
transportation electronics. Manufacturers, assemblers, and installers of
radio-telephone or other two-way communication radios have the sole
responsibility to correctly install and integrate those devices into Allison
Transmission-equipped vehicles to customer satisfaction.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
(DNS) Do Not Shift Light
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
4th Generation Codes
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 3000/4000 Series Trouble codes
4th Generation Codes
Electronic Controls: Basic understanding of Allison electronic
controls to include the following:
1000/2000 Series Accessing Diagnostic Trouble codes
Allison DOC® For PC–Service Tool is Used
In addition to viewing DTCs, the Allison DOC® For PC–Service Tool
may also be used to display the amount of transmission operation
from the initial service indication until the service reset.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 1000/2000 Series Trouble codes
Check Transmission Light Action
Failure to attend to the service condition and reset the TRANS
SERVICE indicator within a defined operating period results in the
illumination of the CHECK TRANS light (in addition to the TRANS
SERVICE light), indicating the increased probability that the service
condition may/will develop into a more serious condition.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 1000/2000 Series Trouble codes
Check Transmission Light Action
The TRANS SERVICE indicator can be reset with the Allison DOC® For
PC–Service Tool. It may also be reset by selecting N (Neutral)D (Drive)
N (Neutral) D (Drive) N (Neutral) R (Reverse) N (Neutral) on the shift
selector, pausing briefly (less than three seconds) between each
selector movement, with the ignition on and the engine not running.
Electronic Controls: Basic understanding of Allison electronic
controls to include the following: 1000/2000 Series Trouble codes
Check Transmission Light Action
Failure to perform maintenance and reset the TRANS SERVICE
indicator within the next 100 hours of transmission operation will
result in the illumination of the CHECK TRANS light (in addition to the
TRANS SERVICE light). Any time this light is illuminated, the TCM
registers a Diagnostic Trouble Code (DTC), which requires the use
of Allison DOC® For PC–Service Tool to clear the code.
Output Retarder: Components MT and HT Descriptions
RETARDER
The self-contained retarder is at the output of the transmission and consists of a
vaned rotor which rotates in a vaned cavity. The rotor is splined to and driven by
the output shaft. When the retarder is activated, the fluid in the accumulator is
displaced into the retarder cavity. The pressurized fluid in the cavity acting against
the rotating and stationary vanes causes the retarder rotor and output shaft to
reduce speed, slowing the vehicle or limiting speed on a downhill grade.
When the retarder is deactivated, the retarder cavity is evacuated and the
accumulator is recharged with fluid.
Output Retarder: Components MT and HT Descriptions
The output retarder is located in the rear of the transmission and consists of a
multiplate clutch pack and a vaned rotating element. When the retarder is
applied, a control valve instantly releases fluid to fill the retarder cavity and
applies the retarder clutch. The clutch and the rotating element act together to
quickly slow the vehicle.
The MT 600 Series output retarder is mounted on the rear of the transmission as
an integral part of the transmission and provides your vehicle with an auxiliary
retardation system to slow the vehicle. The unit combines hydraulic and friction
clutch retardation capabilities. In many applications, the retarder is applied in
conjunction with the service brakes.
Input Retarder: Components MT and HT Descriptions
The input retarder is located between the converter housing and the
transmission main housing. The retarder consists of a vaned rotating element that
is splined to the input shaft. When the retarder is applied, a control valve fills the
retarder cavity with fluid and slows the vehicle.
The HT 700 Series retarder, located between the torque converter and the
transmission gearing, provides hydraulic retardation capabilities to slow the
vehicle. Maximum retarder effect in this series occurs at high input speed.
Selecting a lower hold range position when using this type retarder is
recommended for maximum effect.
Retarder Accumulator
The accumulator is a remotely mounted, sealed, cylindrical container that
contains a reserve quantity of transmission fluid for initial fill of the retarder. The
accumulator is connected to the retarder by a Size 20 hose. Also connected to the
accumulator is the vehicle’s air system through an air regulator/pressure
protection valve.
Retarder Accumulator
Transmission fluid stored in the accumulator is discharged into the retarder by a
piston located in the accumulator. This piston is forced toward the right-side of
the accumulator by air pressure only. Once the retarder is deactivated, air
pressure is exhausted on the left-side of the piston and retarder pressure pushes
the piston back to the left side of the accumulator. This recharges the
accumulator until the next retarder application. After the retarder flow valve
shifts, converter out pressure is aligned to the cooler circuit which keeps the
accumulator charged.
Output Retarder: Accumulator
Retarder Fluid Temperature
Retarder Temperature Indicator—This signal from the TCM activates an indicator
light when retarder temperature has exceeded a calibration limit.
The retarder temperature sensor sends retarder temperature information to the
TCM. The TCM uses this data to:
• Turn on a dash light to alert the operator when an over-temp condition is
present.
• Log diagnostic codes.
• Reduce retarder capacity in over-temp situations.
• Invoke a preselected downshift.
• Control retarder torque to requested level.
Retarder Fluid Temperature
Retarder capacity is reduced if the transmission retarder-out or transmission
sump temperature exceeds specified limits, as detected by temperature sensors
which are integral to the transmission. In addition, retarder capacity is reduced in
the event of elevated engine water temperature based on:
• engine water temperature as communicated to the TCM with an engine coolant
sensor or via an SAE J1939 or J1587 datalink, or
• detection by an engine water temperature sensor which provides an analog input
signal to the TCM. This sensor is supplied and installed by the vehicle builder.
Retarder Fluid Temperature
BASED ON RETARDER TEMPERATURE
If the retarder temperature exceeds 143ºC (290ºF), the TCM raises the closed
throttle downshift points by activating the preselect downshift schedule. Use of
the preselect downshift schedule forces downshifts to occur at higher than
normal road speeds, increasing coolant flow through the transmission cooler and
engine radiator. If the retarder temperature exceeds 149ºC (300ºF), retarder
capacity begins to reduce. Capacity reduction continues until it is reduced to
approximately 27% of the maximum available retarder capacity.
Retarder Fluid Temperature
BASED ON RETARDER TEMPERATURE
If the retarder temperature exceeds 166ºC (330ºF), the retarder temperature
indicator output activates. This illuminates a retarder over-temperature
Light that alerts the operator of excessive retarder temperature. The retarder
temperature light deactivates when the retarder temperature drops below
159ºC (318ºF). If the retarder temperature remains above 166ºC (330ºF) for
ten consecutive seconds, an active DTC P2740 (retarder oil temperature
hot) is logged by the TCM. When the temperature drops and remains below
166ºC (330ºF) for ten consecutive seconds, the DTC becomes inactive and
is stored in memory.
Retarder Fluid Temperature
BASED ON TRANSMISSION SUMP TEMPERATURE
Independent of the retarder temperature, if the transmission sump
temperature exceeds 117ºC (240ºF), retarder capacity will similarly be
reduced as described above. The over-temperature indicator is activated and the
over-temp DTC is logged if the sump temperature exceeds 121ºC (250ºF) for fifteen
minutes, exceeds 128ºC (262ºF) for more than one minute, or instantaneously
reaches 132ºC (270ºF).
Retarder Fluid Temperature
NOTE: When the transmission fluid or engine water temperature
(engine water temperature is an OEM option) exceeds programmed limits,
retarder capacity is automatically gradually reduced to minimize or avoid
possible system overheating.
Output Retarder: Activation Signal
Retarder Fluid Level
NOTE: When reduced retarder performance is observed, be sure the
transmission fluid level is within the operating band on the dipstick.
Low fluid level is a common cause for retarder performance
complaints.
Output Retarder: Oil Cooler
COOLER CIRCUIT
The transmission fluid is cooled by an integral (transmission-mounted) or remotemounted oil cooler. Connections to the cooling circuit are located at the front or
rear of the transmission to facilitate installation of remote cooler lines. On
retarder models, only the rear cooler ports may be used. The integral cooler is
mounted on the lower rear portion of the transmission, replacing the remote
cooler manifold. Integral cooler oil ports are internal requiring coolant to be
routed to and from the cooler.
Output Retarder: Oil Cooler
COOLER CIRCUIT
The retarder housing allows the addition of either a remote or integral cooler for
transmission sump fluid in addition to retarder out fluid. A bypass cover is placed
over the sump cooling ports when the provision is not used. The sump cooler
ports are located on the lower right rear face of the retarder housing
Output Retarder: Safety Feature
Regardless of the type of Allison retarder controls on your vehicle, the following
safety features are common to each configuration:
• The retarder can be disabled when inclement weather or slippery road
conditions are present.
• Vehicle brake lights should always be on when the retarder is applied
(periodically verify that they are working).
• Anti-lock brake systems send a signal to the transmission TCM/ECU to indicate
that the brake system is activated.
Output Retarder: Safety Feature
The retarder is automatically disabled and the lockup clutch is
disengaged whenever the vehicle anti-lock brake system (ABS) is active.
However, in case the ABS system malfunctions, it is recommended that
the retarder enable switch, if present, be disabled.
Understanding of Allison Reference Material:
Performing a Transmission Stall Test.
1. Start the engine. While in neutral let the transmission warm to normal operating
temperature:
• Sump temperature 71–93°C (160–200°F)
• Converter out temperature 82–104°C (180–220°F)
2. Perform a hot check of the transmission fluid level and adjust as necessary.
3. Turn all engine accessories OFF.
4. To place Allison DOC® For PC–Service Tool in clutch test mode, select D (Drive)
on the shift selector, then select 4 (Fourth Range) on the Range Panel.
Understanding of Allison Reference Material:
Performing a Transmission Stall Test.
NOTE: Do not use the shift selector to try and attain 4 (Fourth Range). Using 4
(Fourth Range) from the shift selector reduces the torque imposed on the
transmission driveline. Do not perform a transmission stall test in R (Reverse). Make
sure you select 4 (Fourth Range) from the Range Panel displayed on the computer
screen during the clutch test mode.
Understanding of Allison Reference Material:
Performing a Transmission Stall Test.
CAUTION: To help avoid transmission or driveline damage, full throttle stall tests
must not be performed in R (Reverse) range, all models, or low ranges, 7speed
models.
5. Notify personnel in the area to keep clear of the vehicle.
6. Slowly increase engine rpm until engine speed stabilizes.
7. Record engine speed.
Understanding of Allison Reference Material:
Performing a Transmission Stall Test.
CAUTION: The transmission stall test procedure causes a rapid rise in transmission
fluid temperature that can damage the transmission. Never maintain a stall
condition once engine speed stabilizes or converter out (to cooler) temperature
exceeds 150°C (300°F). During a stall condition, converter out temperature rises
much faster than the internal (sump) temperature. Never use sump fluid
temperature to determine the length of the stall condition. If the stall test is
repeated, do not let the engine overheat.
Understanding of Allison Reference Material:
Performing a Transmission Stall Test.
8. Record converter out (to cooler) temperature.
9. Reduce the engine speed to idle and shift the transmission to N (Neutral).
10. Raise engine speed to 1200–1500 rpm for 2 minutes to cool transmission fluid.
11. At the end of two minutes, record converter out (to cooler) temperature.
12. Proceed to 2.13.7 Neutral Cool-Down Check Procedure.
This will complete the EVT F-6
Preparation Presentation.
Good Luck on the Examination.