Page 1
Mechanic’s Tips
AT 500 and AT 1500
Series Transmissions
MT1321EN
MT4108EN
Page 2
Mechanic’s
Tips
Allison Transmission
AT 540, AT 543
AT 542, AT 542N, AT 542R, AT 542NR
AT 545, AT 545N, AT 545R, AT 545NR,
AT 542NFE
AT 1542, AT 1542P, AT 1542NP
AT 1545, AT 1545P, AT 1545NP
MT1321EN
Printed in U.S.A.
June 1996
Revision 1, 1999 Apri
Copyright © 2007 Allison Transmission, Inc.
l
Page 3
WARNINGS, CAUTIONS, AND NOTES
IT IS YOUR RESPONSIBILITY to be completely familiar with the warnings and
cautions described in this handbook. It is, however, important to understand that
these warnings and cautions are not exhaustive. Allison Transmission could not
possibly know, evaluate, and advise the service trade of all conceivable ways in
which service might be done or of the possible hazardous consequences of each
way. Consequently, Allison Transmission has not undertaken any such broad
evaluation. Accordingly, ANYONE WHO USES A SERVICE PROCEDURE OR
TOOL WHICH IS NOT RECOMMENDED BY ALLISON TRANSMISSION
MUST first be thoroughly satisfied that neither personal safety nor equipment safety
will be jeopardized by the service methods selected.
Proper service and repair is important to the safe, reliable operation of the
equipment. The service procedures recommended by Allison Transmission and
described in this handbook are effective methods for performing service operations.
Some of these service operations require the use of tools specially designed for the
purpose. The special tools should be used when and as recommended.
Three types of headings are used in this manual to attract your attention. These
warnings and cautions advise of specific methods or actions that can result in personal
injury, damage to the equipment, or cause the equipment to become unsafe.
WARNING:
etc., if not correctly followed, could result in personal injury or loss of life.
CAUTION:
practice, etc., if not strictly observed, could result in damage to or
destruction of equipment.
NOTE:
essential to highlight.
A warning is used when an operating procedure, practice,
A caution is used when an operating procedure,
A note is used when an operating procedure, practice, etc., is
ii
Page 4
TABLE OF CONTENTS
Paragraph Description Page
Section I PREVENTIVE MAINTENANCE
1–1 Periodic Inspection and Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1–2 Importance of Proper Fluid Level . . . . . . . . . . . . . . . . . . . . . . . 1
1–3 Dipstick Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1–4 Fluid Check Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1–5 Keeping Fluid Clean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1–6 Recommended Automatic Transmission Fluid
and Viscosity Grade. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1–7 Fluid and Filter Change Intervals. . . . . . . . . . . . . . . . . . . . . . . . 5
1–8 Fluid and Filter Change Procedure . . . . . . . . . . . . . . . . . . . . . . 6
1–9 Fluid Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1–10 Auxiliary Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1–11 Breather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1–12 Transmission Stall Test and Neutral
Cool–Down Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Section II REMOVING TRANSMISSION
2–1 Draining Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2–2 Disconnecting Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2–3 Uncoupling Engine From Driveline. . . . . . . . . . . . . . . . . . . . . 14
2–4 Removing Mounting Bolts. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2–5 Removing Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2–6 Repair Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Section III PREPARING TRANSMISSION FOR INSTALLATION
3–1 Checking Input Components . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3–2 Checking Torque Converter Position. . . . . . . . . . . . . . . . . . . . 17
3–3 Installing Parking Brake and Output Flange . . . . . . . . . . . . . . 18
3–4 Installing Shift Selector Lever . . . . . . . . . . . . . . . . . . . . . . . . . 19
3–5 Installing Power Takeoff (PTO). . . . . . . . . . . . . . . . . . . . . . . . 20
3–6 Installing Shift Modulation Control. . . . . . . . . . . . . . . . . . . . . 21
3–7 Installing Fill Tube and Drain Plug . . . . . . . . . . . . . . . . . . . . . 22
3–8 Installing Neutral Start and Reverse Signal Switches . . . . . . . 23
3–9 Installing Retarder Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3–10 Checking Breather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
iii
Page 5
Paragraph Description Page
Section IV PREPARING VEHICLE FOR TRANSMISSION
INSTALLATION
4–1 Checking Flexplate, Engine Features. . . . . . . . . . . . . . . . . . . . 25
4–2 Checking Chassis, Driveline . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4–3 Checking Cooler, Tubes, Hoses, Fittings. . . . . . . . . . . . . . . . . 27
4–4 Checking Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Section V INSTALLING TRANSMISSION INTO VEHICLE
5–1 Handling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5–2 Coupling to Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5–3 Installing Transmission Mounting Components . . . . . . . . . . . 30
5–4 Coupling to Driveline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5–5 Installing Vacuum or Air Modulator Control . . . . . . . . . . . . . 31
5–6 Connecting Cooler, Vacuum Lines, Air Lines. . . . . . . . . . . . . 32
5–7 Connecting Retarder Controls . . . . . . . . . . . . . . . . . . . . . . . . . 32
5–8 Connecting Shift Selector Control. . . . . . . . . . . . . . . . . . . . . . 33
5–9 Installing, Adjusting Mechanical Modulator Control . . . . . . . 34
5–10 Connecting Power Takeoff Controls . . . . . . . . . . . . . . . . . . . . 35
5–11 Connecting Parking Brake Control . . . . . . . . . . . . . . . . . . . . . 35
5–12 Connecting Speedometer Drive . . . . . . . . . . . . . . . . . . . . . . . . 35
5–13 Filling the Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Section VI CHECKS AND ADJUSTMENT
6–1 Installation Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
6–2 Road Test and Vehicle Operation Checklist . . . . . . . . . . . . . . 40
Section VII CUSTOMER SERVICE
7–1 Owner Assistance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
7–2 Service Literature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
iv
Page 6
PREFACE
This handbook is a ready reference for the mechanic removing, installing, or
maintaining AT Series Automatic Transmissions. All features of both the vehicle and
transmission that become involved in the installation procedures are discussed. The
information presented will help the mechanic to remove, install, and maintain the
transmission in a manner that assures satisfactory operation and long service life.
TRADEMARKS USED
DEXRON
®
Loctite
®
Teflon
is a registered trademark of the DuPont Corporation
®
is a registered trademark of General Motors Corporation
is a registered trademark of the Loctite Corporation
v
Page 7
vi
Model AT 542 Transmission — Left-Front View
Model AT 545 Transmission — Right-Front View
Model AT 545R Transmission — Right-Front View
Page 8
PREVENTIVE
S
ECTION
MAINTENANCE
I
1–1. PERIODIC INSPECTION AND CARE
Clean and inspect the exterior of the transmission at regular intervals. The severity
of service and operating conditions will determine the frequency of such
inspections. Inspect the transmission for the following items:
•
Loose bolts (transmission and mounting components)
•
Fluid leaks (correct immediately)
•
Shift linkage freely positioned by transmission detent
•
Full (and ease of) movement of mechanical modulator linkage
•
Vacuum leaks in the air line and modulator
•
Damaged or loose fluid lines
•
Worn or frayed electrical connections
•
Worn, out-of-phase driveline U-joints and slip fittings
•
Loose or missing speedometer cable fittings
•
Damaged PTO linkage and driveline
Check transmission fluid regularly . Once consistent daily hot le vel checks ha ve been
established, and daily inspection shows no sign of transmission leakage, less
frequent checks can be made.
1–2. IMPORTANCE OF PROPER FLUID LEVEL
Because the transmission fluid cools, lubricates, and transmits hydraulic
power, it is important that the proper fluid le v el be maintained at all times.
If the fluid level is too low, the converter and clutches will not receive an
adequate supply of fluid. If the level is too high, the fluid will aerate, the
transmission will overheat, and fluid may be expelled through the breather
or dipstick tube.
1–3. DIPSTICK MARKINGS
Earlier models use a dipstick marked FULL and ADD (Figure 1–1). Later models
use a dipstick marked COLD RUN and HOT RUN. Figure 1–2 illustrates the marks
in relation to the transmission.
1
Page 9
NOTE:
The ADD and FULL dimensions on earlier dipsticks coincide
with the HOT RUN band dimensions on later dipsticks.
TRANS
HOT
FULL
ADD
EARLIER
MODELS
MODELS
TOP OF OIL PAN
EARLIER
MODELS
FULL
0.50 in.
ADD
(12.7 mm)
1.00 in.
(25.4 mm)
1.50 in.
(38.1 mm)
1.80 in.
(45.7 mm)
IN
NEUTRAL
®
OIL
TOP OF OIL PAN
0.50 in.
CHECK IN NEUTRAL
HOT
COLD
RUN
AT IDLE
USE DEXRON
RUN
(12.7 mm)
1.00 in.
(25.4 mm)
(38.1 mm)
NOTE: This illustration is not a template,
placement of markings will vary according
LATER
to the installation angle of the dipstick tube.
Figure 1–1. Typical Dipstick Markings
FILL TUBE ADAPTER HOLE
DRAIN PLUG
OIL PAN
1.50 in.
1.80 in.
(45.7 mm)
V03004
LATER
MODELS
HOT RUN
COLD RUN
V03005
Figure 1–2. How Fluid Levels Are Established
2
Page 10
•
•
•
1–4. FLUID CHECK PROCEDURE
WARNING: When checking the fluid level, be sure the transmission
is in N ( Neutral) or P ( Park), parking brake and/or emergency brakes
are set and properly engaged, and the wheels are chocked.
Unexpected and possible sudden vehicle movement may occur if
these precautions are not taken.
CAUTION : Dirt and foreign matter must not be permitted to enter
the fluid system. It can cause valves to stick, cause undue wear of
transmission parts, or clog passages.
Always check the fluid level a minimum of two times. Consistency is important in
maintaining accuracy. If inconsistent readings persist, check the transmission
breather and the vent hole in the dipstick fill tube to ensure they are clean and free of
debris. The vent hole is located on the underside of the fill tube just below the seal of
the dipstick cap.
Check the fluid level by the following procedures and record any abnormal fluid
level, milky appearance, or any trace of coolant in the fluid on your maintenance
records. Refer to Paragraph 1–8.
a.
Cold Check
NOTE: The only purpose of the Cold Check is to determine if the
transmission has enough fluid to be safely operated until a Hot Check
can be made.
Park the vehicle on a level surface, set the parking brake and/or emergency
brakes, and chock the vehicle wheels.
Run the engine at 1000–1500 rpm for one minute to purge air from the
system. Return engine to idle, then shift to D (Drive) and then to R (Reverse)
to fill the hydraulic circuits with fluid. Then, shift to N (Neutral) or P (Park)
and allow the engine to idle (500–800 rpm). The sump temperature should be
between 60–120°F (16–49°C).
CAUTION : The fluid level rises as sump temperature increases. DO
NOT fill above the COLD RUN band if the transmission fluid is
below normal operating temperature.
Clean around the end of the fill tube before removing the dipstick. Wipe the
dipstick clean and check the fluid level. If the fluid on the dipstick is within
the COLD RUN band, the level is satisfactory for operating the transmission
3
Page 11
•
•
•
•
until the fluid is hot enough to perform a HOT R UN check. If the fluid le v el is
not within the COLD RUN band, add or drain fluid as necessary to bring the
level to the middle of the COLD RUN band.
Perform a hot check at the first opportunity after the normal operating sump
temperature 160–200°F (71–93°C) is reached.
b.
Hot Check
NOTE: The fluid level rises as the temperature increases. To ensure
an accurate check, operate the transmission until the sump fluid
temperature is 160–200°F (71–93°C); converter-out temperature is
180–220°F (82–104°C).
Park the vehicle on a lev el surface and shift to N (Neutral) or P (Park). Set the
parking brake and/or emergency brakes and chock the vehicle wheels. Allow
the engine to idle (500–800 rpm).
Wipe the dipstick clean and check the fluid level. The safe operating range is
any level within the HOT RUN band on the dipstick. If the level is not within
this band, add or drain fluid as necessary to bring the level to the top of the
HOT RUN band. Approximately 1 quart (1 liter) of fluid is required to raise
the level from the bottom to the top of the band.
1–5. KEEPING FLUID CLEAN
˙
It is absolutely necessary that the fluid put into the transmission be clean. Fluid
must be handled in clean containers, fillers, etc., to prevent foreign material from
entering the transmission. Lay dipstick in a clean place while filling the
transmission.
CAUTION : Containers or fillers that have been used to handle any
antifreeze or engine coolant solution must not be used for
transmission fluid. Antifreeze and coolant solutions contain ethylene
glycol which, if introduced into the transmission, can cause the clutch
plates to fail.
1–6. RECOMMENDED AUTOMATIC TRANSMISSION FLUID
AND VISCOSITY GRADE
Hydraulic fluids (oils) used in the transmission are important influences on
transmission performance, reliability, and durability. DEXRON
recommended for on-highway applications. T ype C-4 fluids are recommended
for severe duty and off-highway applications.
4
®
-III fluids are
Page 12
•
•
P
Some DEXRON
®
fluids are also qualified as Type C-4 fluids. To ensure the
fluid is qualified for use in Allison transmissions, check for a DEXRON
C-4 fluid license, or approval numbers on the container, or consult the
lubricant manufacturer. Consult your Allison Transmission dealer or
distributor before using other fluid types; fluid types such as Type F and
universal farm fluids may or may not be properly qualified for use in your
Allison transmission.
CAUTION : Disregarding minimum fluid temperature limits can
result in transmission malfunction or reduced transmission life.
When choosing the optimum viscosity grade of fluid to use, duty cycle,
preheat capabilities, and/or geographical location must be taken into
consideration. Table 1–1 lists the minimum fluid temperatures at which the
transmission may be safely operated. Preheat with auxiliary heating
equipment or by running the vehicle with the transmission in N (Neutral) or
(Park) for a minimum of 20 minutes before attempting range operation.
Table 1–1. Transmission Fluid Operating Temperature Requirements
Viscosity Grade
Ambient T emperatur e Below Which Preheat
Is Required
Fahrenheit Celsius
®
or
SAE 0W-20 (Arctic) –31 –35
DEXRON
®
-III
–22 –30
SAE 10W –4 –20
SAE 15W-40 5 –15
SAE 30 32 0
SAE 40 50 10
1–7. FLUID AND FILTER CHANGE INTERVALS
Fluid and filter change frequency is determined by severity of
transmission service and by the filter equipment installed. Table 1–2 is a
general guide. More frequent changes may be required when operations
are subject to high levels of contamination or ov erheating.
5
Page 13
6
•
•
•
Table 1–2. Fluid and Filter Change Intervals
AT
Transmission
On-Highway,
Light-Duty
Fluid Change Internal Sump
Paper Filter:
25,000 miles
(40 000 km)
or 12 months*
Brass Filter :
50,000 miles
(80 000 km)
Paper Filter: at
each fluid change
interval
Brass Filter:
50,000 miles
(80 000 km) with
no time limit
External Auxiliary
Filters**
After first 5000
miles (8 000 km)
and at 25,000 miles
(40 000 km)
or 12 months,
thereafter*
or 24 months*
On-Highway,
Heavy-Duty,
Retarder
Paper or Brass
Filter: 25,000
miles (40 000 km)
or 12 months*
Paper Filter: at
each fluid change
interval
Brass Filter:
50,000 miles
After first 5000
miles (8 000 km)
and at normal fluid
change intervals,
thereafter*
(80 000 km) with
no time limit
Off-Highway
Paper or Brass
Filter : 1000 hours
max or 12 months*
Paper or Brass
Filter: at each fluid
change interval
After first 500 hours,
and at normal fluid
change intervals
thereafter*
* Whichever occurs first.
**
When an Allison high-efficiency filter is used, the change interval is until the Change Filter light
indicates the filter is contaminated or until it has been in use for three years, whichever occurs first.
No mileage restrictions apply.
A brass screen sump filter is available for all AT 500 and AT 1500 Series
transmissions for both the shallow pan and the deep pan models. To convert an
AT deep pan 5.3 inches (135 mm) with paper filter to the brass screen filter
configuration, a service conversion kit is required. Refer to Service Information
Letter (SIL) 5-TR-93 (latest revision).
1–8. FLUID AND FILTER CHANGE PROCEDURE
a. Drain
The transmission should be at operating temperature to assist
draining.
Remove the drain plug from the pan. Disconnect the fill tube from the pan
only if required.
Examine the drained fluid for evidence of contamination (refer to Paragraph 1–9).
Page 14
•
•
•
•
•
•
•
•
Remove the pan and filter. Discard the pan gasket, filter, and filter tube
sealring. Clean the pan.
Remove, clean, and reinstall the governor feed line screen in the control
valve body.
For models with the shallow pan (3.8 inch, 97 mm), insert a new sealring into
the filter tube. Install the filter tube into the main housing. Install a new brass
screen sump filter onto the filter tube. Bolt the filter onto the transmission.
Replace the pan gasket and reattach the pan (reference Transmission Service
Manual). Tighten the pan screws to 10–15 lb ft (14–20 N·m).
NOTE: To prevent leakage, pan washer-head screws must retain a
5 lb ft (7 N·m) minimum torque after gasket sets.
Install the drain plug into the pan and tighten it to 15–20 lb ft (20–27 N·m). If
removed, install the fill tube and tighten the fill tube fitting in the pan boss to
65–75 lb ft (88–102 N·m).
For models with the deep pan (5.3 inch, 135 mm), insert a new sealring into
the filter tube. Install the filter tube into the main housing. When converting
from paper filter to brass screen filter, and for servicing the pan with the brass
screen filter, attach filter bracket (see SIL 5-TR-93). Install the brass screen
sump filter onto the filter tube. Bolt the filter to the filter bracket. Replace the
pan gasket and reattach the pan (reference Transmission Service Manual).
Tighten the pan screws to 10–15 lb ft (14–20 N·m).
•
•
NOTE: To prevent leakage, pan washer-head screws must retain a
5 lb ft (7 N·m) minimum torque after gasket sets.
Install the drain plug into the pan and tighten it to 15–20 lb ft (20–27 N·m). If
removed, install the fill tube and tighten the fill tube fitting in the pan boss to
65–75 lb ft (88–102 N·m).
If an external auxiliary filter is present, replace the filter element. Refer to
Table 1–2 for replacement intervals.
b.
Fill
Refill the transmission. (Refer to Paragraph 1–6, and to Table 1–3.)
The refill amount is less than the initial fill because some of the fluid remains
in the external circuits and transmission cavities.
Check the fluid level as outlined in Paragraph 1–4.
7
Page 15
Table 1–3. Transmission Fluid Refill Capacities
Pan T ype Quantity
Shallow pan — 3.8 inches (97 mm) 9 U.S. qt. (8.5 liters)*
Deep pan — 5.3 inches (135 mm) 16 U.S. qt. (15 liters)*
* The amount of transmission fluid shown in the following chart does not include the
amount required to fill the external circuits.
1–9. FLUID CONTAMINATION
Examine at Fluid Change
a.
At each fluid change, examine the fluid which is drained for evidence of dirt or
engine coolant (water). A normal amount of condensation will emulsify in the fluid
during operation of the transmission. However, if there is evidence of coolant, check
the cooler (heat exchanger) for leakage between the cooler and fluid areas. Fluid in
the coolant side of the cooler (heat exchanger) is another sign of leakage. This,
however, may indicate leakage from the engine oil system.
b.
Metal Particles
8
CAUTION:
If excessive metal contamination has occurred,
replacement of the cooler and replacement of all bearings within the
transmission is recommended.
Metal particles in the fluid (except for the minute particles normally trapped in the
filter) indicate damage has occurred in the transmission. When these particles are
found in the sump, the transmission may need to be disassembled and closely
inspected to find the source. Metal contamination requires complete disassembly of
the transmission and cleaning of all internal and external circuits, cooler, and all
other areas where the particles could lodge. (Refer to Paragraph 1–10, Auxiliary
Filter.)
c.
Coolant Leakage
If engine coolant leaks into the transmission hydraulic system, take immediate
action to prevent malfunction and possible serious damage. Completely
disassemble, inspect, and clean the transmission. Remove all traces of the coolant
and varnish deposits resulting from coolant contamination. Replace friction clutch
plates contaminated with ethylene glycol.
Page 16
d.
Fluid Analysis
Transmission protection and fluid change intervals can be optimized by monitoring
oxidation according to the tests and limits shown in Table 1–4. Consult your local
telephone directory for fluid analysis firms. Use one fluid analysis firm as results
from various firms cannot be accurately compared. Refer to the Technicians’ Guide
for Automatic Transmission Fluid (GN2055EN) for additional information.
Table 1–4. Fluid Oxidation Measurement Limits
Measurement Limit
Viscosity
Carbonyl absorbance
Total acid number
Solids
A =
*
Absorbance units.
±25% change from new fluid
+0.3 A*/0.1 mm change from new fluid
+3.0 change from new fluid
2% by volume maximum
1–10. AUXILIARY FILTER
If a condition occurs that introduces debris into the transmission hydraulic system, a
complete cleanup of the cooler and lines is recommended.
Because repeated cleaning and flushing may not remove all debris, installation of an
auxiliary filter in the cooler-out line (between cooler and transmission) is
recommended. This recommendation applies whether the transmission is
overhauled or replaced by a new or rebuilt unit.
CAUTION:
DO NOT install an auxiliary filter in the AT 500R
primary cooler circuit. This reduces retarder effectiveness. An
auxiliary filter in the secondary cooler circuit is sufficient.
If any doubt exists about the cleanup of the cooler, replace the cooler.
The auxiliary filter should have at least a 40-micron filter element or finer and a
maximum filter pressure drop of 3 psi (21 kPa) at 4.5 gpm (17 liters/minute) at
180˚F (82˚C). The maximum external circuit pressure drop must not exceed 35 psi
(241 kPa) at 4.5 gpm (17 liters/minute) at operating temperature, in N (Neutral), and
at 2400 rpm.
9
Page 17
The following auxiliary filters are recommended:
Table 1–5. Auxiliary Filter Recommendations
Filter Assembly Filter Element
Allison 29510923*
AC PM 13-16
AC PM 16-1
FX 11583
Fram HP 1-1
Purolator OF-15C-1
Purolator 20-10
* High-efficiency filter and element are available from your authorized Allison distributor.
Ref: SIL 12-TR-93 (latest revision)
Allison 29510922*
PF 897
PF141
HF6520
HP 1 or AC HD 222
OF-2C-1
PER-20
1–11. BREATHER
The breather is located at the top of the transmission housing. It serves to prevent
pressure buildup within the transmission; it must be kept clean and the passage must
be kept open. The prevalence of dust and dirt will determine the frequency at which
the breather requires cleaning. Use care when cleaning the transmission. Spraying
steam, water, or cleaning solution directly at the breather can force the water or
solution into the transmission.
1–12. TRANSMISSION STALL TEST AND NEUTRAL
COOL-DOWN CHECK
a.
Purpose
The stall test provides a method for determining if the malfunction is in
the engine or in the transmission when a vehicle is not performing
satisfactorily .
The neutral cool-down check utilizes the two minute cooling period on the stall test
to gather fluid temperature data for troubleshooting reference.
NOTE:
Before conducting the stall test, obtain the engine
manufacturer’s data from the engine manufacturer or from your
equipment dealer or distributor.
10
Page 18
b.
Transmission Stall Test Procedure
The engine stall point (rpm) under load is compared to the engine manufacturer’s
specified rpm for the stall test.
WARNING: When conducting a stall test, the vehicle must be
positively prevented from moving. Apply the parking brake and
service brake, and block the vehicle securely. W arn personnel to k eep
clear of the vehicle and its travel path. Failure to do so can cause
serious injury.
CAUTION: Never maintain the stall condition for more than 30
seconds at any one time because of the rapid rise in fluid temperature.
Do not let the converter-out fluid temperature exceed 300°F (149°C).
Do not rely on converter-out fluid temperature to limit stall duration.
During stall conditions, internal temperatures rise much faster than
converter -out fluid temperature. Run the engine at 1200–1500 rpm for
two minutes to cool the transmission fluid between tests. If the stall
test is repeated, do not let the engine overheat.
• Connect a tachometer of known accuracy to the engine, and install a
temperature probe into the converter-out (to cooler) line. Bring the
transmission to the normal operating temperature of 180–220°F (82–104°C).
• With the vehicle securely blocked and the parking brake and service brake
applied, shift to any forward range. Then, accelerate the engine to wide-open
throttle and record the maximum rpm the engine will attain. (This test may
also be conducted in R (Reverse) range if necessary.)
• Reduce engine speed to idle and shift to N (Neutral) or P (Park).
NOTE: Some engines have smoke controls and throttle-delay
mechanisms. These engines require the following stall test procedure:
Put the transmission in the first range hold position. Operate the
vehicle at maximum speed in first range. Apply the vehicle brakes
while maintaining full throttle. As soon as the vehicle is completely
stopped, read the engine rpm (stall speed) from the tachometer.
Reduce engine speed to idle and shift to N (Neutral) or P (Park).
Increase engine speed to cool the torque converter.
11
Page 19
c.
Neutral Cool-Down Check Procedure
The neutral cool-down check determines if the transmission fluid cools following an
engine load condition. Perform this check immediately after the engine speed has
been recorded in the stall test.
• Record the converter-out fluid temperature.
• With the transmission remaining in N (Neutral) or P (Park), run the engine at
1200–1500 rpm for two minutes to cool the fluid.
• At the end of two minutes, record the converter-out fluid temperature.
d. Results
NOTE: Environmental conditions, such as ambient temperature,
altitude, engine accessory loss variations, etc., affect the power input
to the converter. Under such conditions, a stall speed deviation up to
±150 rpm from specification can be accepted as within normal range.
If the engine stall speed is more than 150 rpm below the stall speed specified by the
engine manufacturer, an engine problem is indicated, such as the need for a tune-up.
If the engine stall speed is more than 150 rpm above specification, a transmission
problem is indicated, such as slipping clutches, cavitation, or torque converter
failure.
An extremely low stall speed, such as 33 percent of the specified engine stall rpm,
during which the engine does not smoke, could indicate a free-wheeling torque
converter stator.
If the engine stall speed conforms to specification, but the transmission fluid
overheats, refer to the Neutral Cool-Down Check Procedure. If the fluid does not
cool during the two minute cool-down check, a stuck torque converter stator could
be indicated.
If the engine stall speed conforms to specification and the cool-down check shows
that the transmission fluid cools properly, refer to the applicable AT Service Manual
SM1241EN (latest revision) for troubleshooting procedures.
12
Page 20
REMOVING
SECTION
TRANSMISSION
II
2–1. DRAINING TRANSMISSION
• Remove the drain plug from the pan. Disconnect the transmission fill tube
from the pan only if required. Remove the fill tube completely if it interferes
with transmission removal.
• Examine the drained fluid for evidence of contamination (refer to
Paragraph 1–9).
• Install the drain plug and tighten it to 15–20 lb ft (20–27 N·m).
NOTE: A significant amount of fluid may drain from the hydraulic
lines when they are disconnected from the transmission.
• Disconnect all hydraulic lines from the transmission. Remove the lines from
the vehicle if they interfere with transmission removal. Cap or plug all
hydraulic lines and openings to prevent dirt from entering the hydraulic
system.
2–2. DISCONNECTING CONTROLS
Disconnect the controls from the transmission and position them so they do not
interfere with transmission removal.
• Disconnect all linkage or cables for shifting, shift modulation, parking brake,
and speedometer. Remove the mechanical or electrical modulator control and
plug the opening in the transmission.
• Disconnect the vacuum hose from the vacuum modulator (if used). Remove
the vacuum modulator and plug the opening in the transmission.
• Disconnect the power tak eoff from its driven equipment. Disconnect the PTO
controls. Remove the PTO completely if it will interfere with transmission
removal. Cover the PTO opening.
• Disconnect any electrical leads to the retarder valve body or any sensors or
other equipment on the transmission.
13
Page 21
2–3. UNCOUPLING ENGINE FROM DRIVELINE
• Chock the wheels to prevent the vehicle from rolling.
• Disconnect the vehicle driveline from the transmission output flange
or yoke. Position the drive shaft to avoid interference with
transmission removal.
• Figure 2–1 shows two typical methods of coupling the engine and
transmission. Remove the six driv e co v er bolts (all models except AT 543), or
six flexplate nuts (AT 543).
FLYWHEEL HOUSING
DRIVE COVER
BOLT
FLYWHEEL/RING
GEAR ASSEMBLY
CRANKSHAFT
FLYWHEEL/RING
GEAR ASSEMBLY
DRIVE COVER
NUT
SAE #2
SAE #2
FLYWHEEL HOUSING
SAE #3 TO
SAE #2 ADAPTER
TRANSMISSION
HOUSING
FLEXPLATE
CONVERTER
DRIVE COVER
WEAR PLATE
CONVERTER
PILOT PLATE
WEAR PLATE
CONVERTER
DRIVE COVER
FLEXPLATE
TRANSMISSION
HOUSING
SAE #3 TO
SAE #2 ADAPTER
AT 1500
AT 540
AT 545
AT 543
V03006
Figure 2–1. Typical Coupling Methods
14
Page 22
2–4. REMOVING MOUNTING BOLTS
• Support the transmission securely on a jack, hoist, or other removal support
equipment.
• Remove all bolts and supports that attach the transmission to the vehicle.
NOTE: When an adapter is used to adapt the transmission to a larger
engine flywheel housing (Figure 2–1), remove only the transmissionto-adapter bolts.
• Remove the 10 or 12 bolts that attach the transmission to the engine or
adapter.
2–5. REMOVING TRANSMISSION
CAUTION: Do not pull the transmission away from the torque
converter assembly. The torque converter dri v e co ver must be entirely
free of any restraint by the flexplate driv e or crankshaft pilot when the
transmission separates from the engine.
• Move the transmission rearward until it is clear of the engine. Use
care to prevent the torque converter from separating from the
transmission. Keep the transmission level or the rear slightly low to
prevent the torque converter from slipping forward. Remove the
adapter ring (if used).
• Attach a retaining strap (Figure 2–2) across the converter drive cover and
transmission housing at the earliest opportunity.
2–6. REPAIR INSTRUCTIONS
• Refer to the applicable Allison Transmission Service Manual to repair the
transmission. Refer to Paragraph 7–2.
15
Page 23
TORQUE CONVERTER
RETAINING STRAP
GOVERNOR
COVER
TORQUE
CONVERTER
OIL PAN
SELECTOR
LEVER
MODULATOR
RETAINER
H00387.01
Figure 2–2. Location of Torque Converter Retaining Strap
16
Page 24
PREPARING
SECTION
TRANSMISSION FOR
INSTALLATION
3–1. CHECKING INPUT COMPONENTS
• Check all bolt holes on the front of the flywheel/converter cover/flexplate
adapter. The threads must be undamaged, and the holes free of chips or
foreign material.
• Check the pilot boss (at center of flywheel) for damage or raised metal that
would prevent free entry into the flexplate hub (adapter).
• Check the starter ring gear for excessive wear or damage. Check welds that
retain the ring gear (where applicable).
• Check the transmission mounting flange for gasket remnants, raised metal,
or dirt.
• Inspect the transmission-to-engine mounting flange for raised metal, burrs,
and pieces of gasket material. Remove any of these defects. Inspect the
threaded holes for damaged threads.
3–2. CHECKING TORQUE CONVERTER POSITION
III
When the transmission is installed, the torque converter is axially positioned by the
flexplate. When properly positioned, the torque converter assembly is free of all
restraints against fore and aft movement except for that of the flexplate.
• To determine that there will be ample clearance for positioning the torque
converter, measure as indicated in Figure 3–1. Check the results against the
following dimensions.
— AT 500 and AT 500N Series models with converter build date stamp
before 9/84: 1.600–1.740 inches (40.64–44.19 mm)
— AT 500, AT 500R, and AT 500N Series models with converter build date
stamp of 9/84 or later: 1.581–1.741 inches (40.16–44.22 mm)
— AT 543 models: 1.600–1.721 inches (40.64–43.71 mm)
— AT 1500 Series models: 2.715–2.875 inches (68.96–73.03 mm)
• A measurement outside these dimensions indicates the torque con v erter is not
installed properly. (Refer to the applicable Allison Transmission Service
Manual. Refer to Paragraph 7–2.)
17
Page 25
Measure
over lug
Measure over
retainer and/or
spacer
TRANSMISSION
HOUSING
V03007
LUG
CONVERTER
AT 540
AT 542 SERIES
TRANSMISSION
HOUSING
SPACER OR
SPACER AND
RETAINER
AT 545 SERIES
AT 1500 SERIES
AT 543
Figure 3–1. Converter Position Measurements
3–3. INSTALLING PARKING BRAKE AND OUTPUT FLANGE
CAUTION: Do not attempt to polish the oil seal contact surface on
the flange or yoke. Scratches or machine-type lead can cause seal
leakage.
• Check the output flange rear oil seal to ensure that it has not been damaged
and is free of defects. For replacement instructions, refer to the applicable
Allison Transmission Service Manual. Refer to Paragraph 7–2.
• Lubricate the oil seal with petrolatum or transmission fluid.
• Check the output flange or yoke for damage or wear. Check the oil seal
contact surface to ensure it is smooth and free of surface irregularities to
prevent fluid leaking past the seal. Rotate the flange during installation to
avoid seal lip damage.
• Install the parking brake (if so equipped). Tighten the brake mounting bolts to
81–97 lb ft (110–131 N·m).
CAUTION: Do not use a hammer or similar tool to install the output
flange or yoke onto the transmission output shaft. Internal damage
can result.
• Lubricate the splines of the shaft and output flange and install the output
flange. Ensure the flange hub is seated against the transmission rear bearing.
18
Page 26
• The output flange is retained by a 1⁄2-20 x 11⁄2 inch bolt and a 11⁄16 inch washer.
Replace the bolt and washer each time they are removed. Tighten the bolt to
102–121 lb ft (138–164 N·m).
NOTE: Bolt P/N 29510838 with improved torque retention should be
used. This bolt has five grade identification slots in the bolt head rather
than the six slots of P/N 23014159. Reference SIL 1-TR-94. The
torque value is the same for both bolts.
3–4. INSTALLING SHIFT SELECTOR LEVER
WARNING: Second-neutral models are equipped with an internal
selector lever having two N (Neutral) positions. This style lever may
only be used with second-neutral models. If you mix one- and
second-neutral parts, the unit will not operate properly (e.g. the
vehicle may travel in R (Re v erse) when D (Dri v e) is selected. Be sure
to install the appropriate internal selector lever. Refer to Figure 5–4
and to SIL 20-TR-93.
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
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.
3
⁄8-16 nut (standard inch series). Use of the
• 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.
CAUTION: Overtightening the lever retaining nut can damage the
shaft thread.
• Install the lever retaining nut, finger tight, against the 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.
19
Page 27
Figure 3–2. Tightening Selector Lever Nut
3–5. INSTALLING POWER TAKEOFF (PTO)
CAUTION: Cork or other soft gaskets must never be used to mount
the PTO. Use only shims or gaskets recommended by the PTO
manufacturer.
Space limitations will determine whether the PTO should be installed before or after
the transmission is installed.
• 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.
• Determining PTO Backlash
— PTO not installed: backlash can be measured with special tool J 34814
(Figure 3–3). Reference SIL 50-TR-83 (latest revision).
— PTO installed: measure through the inspection port with a dial indicator
while rotating PTO shaft back and forth. Rattling gears indicate too much
backlash. Difficult engagement or whining gears indicate too tight a fit.
NOTE: One gasket (minimum) is required to prevent fluid leakage.
• 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).
20
Page 28
BASE PLATE
GAUGE PIN
MEASUREMENT
PTO PAD
HOLD DOWN
BOLT
J 34814
TRANSMISSION
MAIN CASE
PTO DRIVE
GEAR
V02394
Measurement Correction
0.011–0.045 in. (0.27–1.16 mm)
0.047–0.070 in. (1.19–1.78 mm)
Figure 3–3. Measuring Turbine-Driven PTO Backlash
one–0.030 in. Gasket (one 0.76 mm Gasket)
two–0.030 in. Gaskets (two 0.76 mm Gaskets)
• 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.)
3–6. INSTALLING SHIFT MODULATION CONTROL
Install the modulation control after the transmission is put into the vehicle. Refer to
Paragraph 5–9.
21
Page 29
PTO DRIVE
GEAR
3RD RANGE CLUTCH
BACKPLATE
Figure 3–4. View at PTO Opening
SNAPRING
H00388.01
3–7. INSTALLING FILL TUBE AND DRAIN PLUG
The fill tube may be installed before the transmission is put into the vehicle, unless
its presence will interfere with transmission installation.
• Install the fill tube and tighten the fitting in the pan boss to
65–75 lb ft (88–102 N·m).
NOTE: Torque was increased to 90–100 lb ft (122–136 N·m)
beginning with S/N 3210685574 where the oil pan boss length was
changed from 0.575 to 0.675 inch. Reference SIL 30-TR-94.
• Fasten the upper end of the fill tube to the engine or transmission with
brackets and bolts as required. Do not attach the fill tube to the vehicle cab or
frame.
• Ensure the drain plug is in place and tightened to 15–20 lb ft (20–27 N·m).
22
Page 30
3–8. INSTALLING NEUTRAL START AND REVERSE
SIGNAL SWITCHES
• Connect any wiring required for sensors, signals, switches, or other electrical
components.
• Install the Neutral Start Switch (if so equipped) into the opening directly
above the selector shaft in the left side of the transmission housing. The
switch must include an aluminum washer (gasket) approximately 0.090 inch
(2.29 mm) thick. The washer on some switches has indentations on one side.
Install the washer onto the switch with the indentations facing away from the
switch. Make sure all mating surfaces are clean and free of contamination.
Apply a light coat of Loctite® pipe sealant with Teflon®, or equivalent, to the
threads of the switch. Install the switch assembly and tighten it to 50–60 lb ft
(68–81 N·m) using installation wrench J 33410.
• If the Neutral Start Switch is not mounted at this location, plug the opening
• Apply a light coat of thread sealant onto the threads of the reverse signal
3
with a
switch. Install the switch into the right side of the transmission. Tighten the
switch to 4–5 lb ft (5–7 N·m). Connect the wire leads.
⁄4-16 plug with its head seated on a rubber-coated washer.
NOTE: An enhanced reverse pressure switch P/N 29503665 became
available in November 1994. The improved switch is stamped with the
3-digit code 484. See SIL 7-TR-95.
3–9. INSTALLING RETARDER CONTROLS
• Be sure that the low speed cutoff switch is reinstalled, if removed, in the
opening provided at the left rear of the transmission. Tighten the switch to
4–5 lb ft (5–7 N·m).
• Be sure that the hose from the main pressure tap on the left side of the
transmission is connected to the fitting on the retarder valve body and that
connections are tightened.
• Be sure that the short hose from the retarder valve body to the “To Cooler”
port is connected and that connections are tightened.
23
Page 31
3–10. CHECKING BREATHER
Ensure the breather is clean and free of obstructions. Also, the breather cap must be
loose and free to rattle. Figure 3–5 shows the two breather configurations.
• The earlier breathers should be equipped with a neoprene shroud
(P/N 6883025). Later models have a breather with an integral shroud. If the
breather shroud is damaged, install a new shroud.
NEOPRENE SHROUD
LATER MODELSEARLIER MODELS
V02884
Figure 3–5. Breather Configurations
24
Page 32
PREPARING VEHICLE
SECTION
FOR TRANSMISSION
INSTALLATION
4–1. CHECKING FLEXPLATE, ENGINE FEATURES
Transmission performance may be adversely affected by improper tolerances
existing between engine-to-transmission mating components. The drive connection
between the engine and transmission converter must transmit engine power,
properly locate and pilot the torque converter, and aid in controlling the forward
thrust of the converter.
Vibration, converter section fluid leaks, a worn front bushing or bearing, and/or a
worn engine crankshaft thrust bearing are frequently the result of exceeding
recommended tolerances in engine-to-transmission mating components. When these
conditions are encountered, certain important measurements should be investigated
before installing a repaired or new transmission.
These measurements are summarized in Table 4–1. Figure 4–1 illustrates the tooling
required for these measurements. Reference SIL 60-TR-81 (latest revision).
IV
Figure 4–1. Tooling Used to Determine the Adaptation
Measurements of an AT 500 Series Transmission
25
Page 33
Table 4–1. Measurements
Component or
Subassembly
Required Inspections Limits
Bore Diameter 16.125–16.130 in.
Flywheel
Housing
Bore Eccentricity* 0.020 in. (0.51 mm) T.I.R.
(409.58–409.70 mm)
Face Squareness* 0.020 in. (0.51 mm) T.I.R.
Crankshaft Hub
and/or Adapter
Converter Pilot
Diameter
Face Squareness 0.0005 in. (0.013 mm) T.I.R.**
Eccentricity
†
Check for Radial
1.703–1.705 in.
(43.26–43.31 mm)
0.010 in. (0.25 mm) T.I.R.
None Permitted
Cracks
Flexplate
Check for Elongated
Mounting Holes
Check for An y Signs of
None Permitted
None Permitted
Distress and/or Wear
Axial Location Flatness
—AT 540/AT 542/
AT 545 models with
1.600–1.740 in.
(40.64–44.19 mm)
converter build date
stamp before 9/84
Mounted
Flexplate
—AT 540/AT 542/
AT 545 models with
converter build date
stamp of 9/84
or later
1.581–1.741 in.
(40.16–44.22 mm)
—AT 543 models 1.600–1.721 in.
(40.64–43.71 mm)
—AT 1500 models 2.715–2.875 in.
(68.96–73.03 mm)
Flatness
—Formed Plates
†† 0.039 in. (0.99 mm)
—Flat Plates 0.157 in. (3.99 mm)
* Limits are for installed engines.
** T.I.R. per inch of diameter.
† Eccentricity with respect to crankshaft center of rotation.
†† A formed flexplate will not be flat, but may have raised areas at the bolt holes and/or have offset
bends in the plate.
26
Page 34
4–2. CHECKING CHASSIS, DRIVELINE
Inspect the chassis and driveline and correct any faulty conditions:
• Broken or worn transmission mounts.
• Missing, cracked, or swollen isolators (rubber mounts).
• Improper or damaged bolts or other hardware.
• Permanent deformation of springs in rear support.
• Damaged or worn cross-frame members.
• Lack of lubrication, excessive end play or wear, or deformation of driveline
midship or hanger bearings.
• Inadequate freedom of movement, wear, excessive backlash, or lack of
lubrication of driveline yoke slip joints.
• Inadequate freedom of movement, wear, lack of lubrication, or damaged
needle bearings in universal joints.
• Nonconformance to manufacturer’ s recommendations for dri veline angles and
universal joint phasing.
• Condition of alignment, flanges, yokes, backlash, fluid leaks, or torque
tightness of mounting bolts for auxiliary transmission or transfer case
mountings.
• Excessive backlash in vehicle differential ring gear and pinion (refer to the
vehicle manufacturer’s specifications).
• Damaged condition or improper alignment of PTO-driven equipment, shafts,
and couplings.
4–3. CHECKING COOLER, TUBES, HOSES, FITTINGS
Inspect chassis and transmission-related plumbing and correct any faulty conditions:
• Transmission hydraulic system cooler (heat exchanger) — clean and flush, or
replace if cleaning and flushing are not satisfactory.
NOTE: There are two coolers to check on an AT 500R transmission.
• Cooler connecting lines –– clean and flush; inspect for deterioration, leaks,
faulty connectors, kinks. Minimum tube size required for cooler circuit is
0.5 inch (12.7 mm) or No. 8 hose size (SAE 13⁄32 inch ID). However, a larger
hose may be required to meet flow and pressure drop requirements. Pay
particular attention to any hose with a Teflon® liner for inner tube kinks or
“bubbles.”
27
Page 35
NOTE: For AT 500R transmissions, the minimum size for primary
cooler hose is No. 16 with a minimum ID of 0.875 inch (22.4 mm) and
for auxiliary cooler hose is No. 8 with a minimum ID of 0.50 inch
(12.7 mm).
• If the hydraulic system has been contaminated with debris, install an auxiliary
filter between the cooler and transmission (in cooler-return line). Refer to
Paragraph 1–10 for filter recommendation and installation details.
• Vacuum or air modulator line and/or hose — inspect for deterioration, bad
connections, loose or missing clamps, or improper routing that causes kinks.
4–4. CHECKING CONTROLS
Inspect transmission control components on vehicle and correct any faulty
conditions:
• Shift selector control — inadequate freedom of movement, frayed or kinked
cables, lack of lubrication, worn rod ends or clevis pins, damaged threads, or
improper routing.
• Mechanical modulator control — inadequate freedom of mov ement, frayed or
kinked cables, lack of lubrication, worn rod ends or clevis pins, damaged
threads, or improper routing.
• Parking brake control — cracks, bends, damaged threads, worn rod ends or
clevis pins.
• PTO control — damage, wear, improper operation, lack of lubrication, or
improper routing.
• Speedometer drive cable — wear, damage, kinks, lack of lubrication,
improper routing, or incorrect drive torque.
• Wiring and related electrical components, sensors, and switches — poor
connections, frayed wiring, or other damage.
28
Page 36
INSTALLING
SECTION
TRANSMISSION INTO
VEHICLE
5–1. HANDLING
CAUTION: The transmission must be handled very carefully after
the torque converter retaining strap is remo ved to a v oid separating the
torque converter from the transmission. K eep the transmission lev el or
the rear slightly lower than the front at all times.
• Remove the torque converter retaining strap when the transmission is in
position for installation.
5–2. COUPLING TO ENGINE
• Align the flexplate and torque converter so that the drive bolts (used
on all models except AT 543) or nuts (AT 543) can be installed
(Figure 2–1). A pilot tool (Figure 5–1) can be used to maintain
alignment on all AT models with drive bolts.
NOTE: If a starter ring gear is welded to the flexplate, the complete
drive connection should be statically or dynamically balanced to
reduce vibration.
V
• Lubricate the center pilot bore and converter nose pilot with molybdenum
disulfide grease.
• Push the transmission toward the engine while guiding the pilot boss on the
drive cover into the center bore and the pilot diameter of the transmission
housing into the flywheel housing bore. If interference is encountered, move
the transmission away from the engine and investigate the cause.
• Install the ten or twelve bolts that secure the transmission housing to the
engine flywheel. Bolts must be installed in the two uppermost bolt holes.
Tighten the bolts to the torque specified by the vehicle manufacturer.
NOTE: The drive cover nuts (AT 543) must be self-locking and
capable of producing a tensile load of 8000 lb (36 kN). A nut that
meets these requirements is Allison P/N 23014107.
29
Page 37
FLYWHEEL
HOUSING
PILOT PLATE
Make from
M-10 x 38 mm
(1.5 in.) Bolt
TAPER
Screwdriver slot
to aid removal
V03008
Figure 5–1. Pilot Tool for Installation (AT 500, AT 1500)
• Tighten the flexplate nuts (AT 543) to 34–40 lb ft (46–54 N·m).
• Tighten the drive cover bolts (all models except AT 543) to 42–50 lb ft
(57–68 N·m).
5–3. INSTALLING TRANSMISSION MOUNTING COMPONENTS
CAUTION:
• For AT 540, AT 542 Series, AT 545 Series, and AT 1500 Series,
mounting pad bolts must penetrate the holes of the mounting
pads 1.24–1.39 inch (31.2–35.5 mm). Tighten mounting pad
bolts to 164–192 lb ft (222–260 N·m).
• For AT 543, mounting pad bolts must penetrate the holes of the
mounting pad 0.775–0.900 inch (19.69–22.86 mm). T ighten
mounting pad bolts to 164–192 lb ft (222–260 N·m).
• Install all bolts, washers, cross-members, supports, and insulators required to
support the transmission in the vehicle frame.
30
Page 38
5–4. COUPLING TO DRIVELINE
• Couple the driveline companion flange or universal joint yoke to the
transmission output flange or yoke.
• Use the bolts, nuts, and torque specified by the vehicle manufacturer.
5–5. INSTALLING VACUUM OR AIR MODULATOR CONTROL
NOTE: There are 12V and 24V electric modulators available as of
June 1994. See SIL 27-TR-94.
• Make sure the original sealring has been removed from the modulator can or
from the counterbore of the transmission housing.
• Install the sealring onto the modulator. Coat the sealring with oil soluble
grease.
• Install the modulator control into the transmission housing. Seat the sealring
in the counterbore in the housing.
• Install the modulator retainer so that the convex side of the curved ends are
toward the transmission. Secure the retainer with a
Tighten the bolt to 10–16 lb ft (19–22 N·m).
• Connect the vacuum or air line to the modulator. The tube connection at the
vacuum modulator should face toward the engine. The routing should be
approximately 10 degrees below horizontal and include a condensate trap
(goose neck) as shown in Figure 5–2.
5
⁄16-18 x 3⁄4 inch bolt.
10°
CONDENSATE TRAP
Figure 5–2. Proper Relation of Vacuum Hose to Modulator Control
31
VACUUM MODULATOR
V03009
Page 39
5–6. CONNECTING COOLER, VACUUM LINES, AIR LINES
• Connect the lines from the transmission to the cooler forming a transmission
fluid-to-water counterflow in the cooler. Vertical-mounted coolers require the
transmission to-cooler line to be connected to the bottom port in the cooler to
avoid air-locking the cooler.
NOTE: On retarder units there are two coolers to connect. See Figure
5–3 for proper location of cooler connections. Tighten cooler fittings
on the primary cooler to 40–50 lb ft (54–68 N·m). Tighten cooler
fittings on the secondary cooler to 15–22 lb ft (20–30 N·m).
• Keep the lines away from exhaust pipes and components that cause chafing.
Avoid kinks and sharp bends. Tighten the cooler SAE No. 8 line fittings that
thread into the transmission housing to 15–22 lb ft (20–30 N·m).
• If a vacuum modulator is used, connect the vacuum modulator line at the
intake manifold.
• If an air modulator is used, connect the air modulator control line at the
control.
5–7. CONNECTING RETARDER CONTROLS
• Connect the wiring harness to the electrical connector on the retarder valve
body (Figure 5–3).
• Insert the temperature sending unit into the retarder valve body (Figure 5–3).
Tighten the sending unit connector to 15–20 lb ft (22–27 N·m).
FROM PRIMARY COOLER
TRANSMISSION “FROM COOLER” PORT
TRANSMISSION “MAIN” PRESSURE TAP
(OPPOSITE SIDE OF TRANSMISSION)
RETARDER VALVE BODY
TEMPERATURE
SENDING UNIT
CONNECTS TO TRANSMISSION
“TO COOLER” PORT
Figure 5–3. AT 500R External Connections
CONNECTS TO
TRANSMISSION
“TO COOLER” PORT
WIRING HARNESS
CONNECTOR
TO PRIMARY COOLER
TO SECONDARY COOLER
L02889.01
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5–8. CONNECTING SHIFT SELECTOR CONTROL
• Place the operator’ s shift selector control at the N (Neutral) position. Place the
selector lever (hidden inside the transmission pan) in the N (Neutral) position
by one of the following two methods (Figure 5–4):
• For vehicles with shift selectors with P (Park) position
— Rotate the selector shaft counterclockwise as far as it will go. This puts
the selector lever in the P (Park) position.
— Carefully rotate the selector shaft clockwise two detents. This puts the
selector lever in the N (Neutral) position.
• For vehicles with shift selectors without a P (Park) position
— Rotate the selector shaft counterclockwise as far as it will go. This puts
the selector lever in the R (Reverse) position.
— Carefully rotate the selector shaft clockwise one detent. This puts the
selector lever in the N (Neutral) position.
• Adjust the linkage so that it matches full movement of the selector lever on
the transmission. Connect the linkage to the selector lever.
• Shift through and check all selector positions to ensure the valve body detent
positions correspond to the respective selector positions and the selector lev er
is freely positioned by the transmission detent.
2N (PARK)
R
N
SECOND-NEUTRAL
RAMP
D3
D
VEHICLES WITH
SHIFT SELECTOR
WITH PARK POSITION
Figure 5–4. Identification of Internal Selector Levers
D1
R
N
D
VEHICLES WITH SHIFT
SELECTOR WITHOUT
PARK POSITION
33
D3
D1
D2
V00386
Page 41
5–9. INSTALLING, ADJUSTING MECHANICAL
MODULATOR CONTROL
NOTE: There are 12V and 24V electric modulators available as of
June 1994. See SIL 27-TR-94.
• Connect the engine (throttle) end of the modulator cable housing to its
mounting.
• Open the engine throttle fully and check whether the throttle linkage will push
or pull the cable core when the throttle linkage is moving toward full throttle
position. If it will push the cable core, then push the cable core until it reaches
the end of its travel. If movement of the throttle linkage toward full throttle
position will pull the cable, then pull the cable to the end of its travel.
• Adjust the clevis or rod end on the cable core until it re gisters with the hole in
the throttle linkage lever and the connecting pin can be freely inserted. With
pin removed, rotate the clevis or rod end one additional turn counterclockwise
(viewing cable core from its end) for pull-type arrangement, or one additional
turn clockwise for push-type arrangement. Install the clevis pin or rod end to
connect the throttle linkage and cable. Tighten the lock nut against the clevis
or rod end. This adjustment assures the ability to achieve full throttle on the
engine without interference from the modulator control.
• Check the travel of the cable core when the throttle is moved from fully open
to fully closed position. The system is designed to provide a travel of 1.187–
1.560 inches (30.15–39.62 mm).
• The most common type of mechanical control is the cable-operated actuator
with a lever to vary the force on the modulator valve. This type of control is
convertible; either push or pull force can be used on the cable when the
throttle is opened. Ensure the modulator control, when connected to the
throttle linkage, provides an increasing force against the modulator actuator
rod in the transmission when the engine throttle is moved toward the open
throttle position.
• Later model actuators include a lev er marked PUSH on one side and PULL on
the opposite side. When the modulator control cover is removed, the word
PUSH or PULL can be seen and indicates how the device is assembled.
• Con version to the opposite mode of operation is only a matter of reassembling
the internal parts. Reverse the positions of the lever, spring, and thimble to
convert it.
• Be sure the modulator control action is as required.
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• Install the O-ring seal onto the modulator control. Coat the O-ring with oil-
soluble grease.
• Install the modulator control into the transmission. Install the control housing,
and secure it with the retainer and the 5⁄16-18 x 3⁄4 inch bolt provided. The
conve x side of the curved ends of the retainer must be to ward the transmission
end against the shoulder of the actuator stem. Tighten the bolt to 10–16 lb ft
(14–22 N·m).
• Some mechanical controls include a support bracket, also secured by the
retainer bolt.
• Check the cable routing. Bends must not be of less than 8 inches (20 cm)
radius. The cable should not be nearer than 6 inches (15 cm) to the engine
exhaust pipe or manifold. The cable must follow the mo vements of the throttle
linkage; it may be necessary to add a spring to ensure the movement occurs
smoothly.
• Adjust other types of mechanical controls as outlined in the vehicle
manufacturer’s instructions.
5–10. CONNECTING POWER TAKEOFF CONTROLS
• If not previously installed, mount the PTO on the transmission. Refer to
Paragraph 3–5 for instructions.
• Connect controls to the PTO. Check for proper operation of the controls.
5–11. CONNECTING PARKING BRAKE CONTROL
• Install the bellcrank support bracket and cable support brackets onto the
transmission housing. Tighten the bolts to 42–50 lb ft (57–68 N·m).
• Connect and properly adjust the parking brake linkage.
• Adjust the brake shoe-to-drum clearance as specified by the manufacturer.
5–12. CONNECTING SPEEDOMETER DRIVE
• Install the speedometer driven gear assembly into the transmission housing.
Tighten to 45–50 lb ft (61–68 N·m). If no speedometer drive is provided, be
sure a steel plug is installed to close the hole in the housing (torque is same as
for driven gear assembly). Do not operate transmission with the plastic
shipping plug in this hole.
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• Install the speedometer drive cable onto the driven gear assembly. Tighten the
cable nut to 50–55 lb in. (5.6–6.2 N·m). Avoid sharp bends in the cable. The
torque required to drive the cable and all associated equipment should not
exceed 25 oz-in. (0.17 N·m).
5–13. FILLING THE TRANSMISSION
• Be sure the transmission hydraulic system is properly filled with fluid before
starting the engine. Refer to Paragraph 1–4.
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CHECKS AND
SECTION
ADJUSTMENTS
6–1. INSTALLATION CHECKLIST
• PROPER TORQUE
❑ Drive cover bolts (AT 540, AT 542, AT 542N, AT 545, AT 545N,
and AT 1500 Series) — 42–50 lb ft (57–68 N·m)
❑ Flexplate nuts (AT 543) — 34–40 lb ft (46–54 N·m)
❑ Transmission-to-engine bolts*
❑ Transmission-to-frame mounting bolts — 164–192 lb ft (220–260 N·m)
❑ Output flange retaining bolt — 102–121 lb ft (138–164 N·m)
❑ Companion flange or universal joints bolts*
❑ Manual selector lever nut — 15–20 lb ft (20–27 N·m)
❑ PTO mounting bolts — 26–32 lb ft (35–43 N·m)
❑ Modulator control retaining bolt — 10–16 lb ft (14–22 N·m)
❑ Parking brake mounting bolts — 81–97 lb ft (110–132 N·m)
VI
❑ Bellcrank and cable support brackets to transmission — 42–49 lb ft
(57–67 N·m)
❑ Hydraulic line fittings in transmission housing or retarder valve
body — 15–22 lb ft (20–30 N·m)
❑ Primary cooler fittings in retarder valve body — 40–50 lb ft (54–68 N·m)
❑ Fill tube fitting — 65–75 lb ft (88–102 N·m) or 90–100 lb ft
(122–136 N·m) with 0.675 inch long oil pan boss
❑ Drain plug — 15–20 lb ft (20–27 N·m)
❑ Speedometer driven gear assembly to rear cover — 45–50 lb ft
(61–68 N·m)
* Tighten to vehicle manufacturer’s specifications.
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• PROPER TORQUE (cont’d)
❑ Neutral start switch to transmission housing — 50–60 lb ft (68–81 N·m)
❑ Reverse signal switch to transmission housing — 4–5 lb ft (5–7 N·m)
❑ Modulator retaining bolt — 10–16 lb ft (14–22 N·m)
❑ Retarder low speed cutoff switch in transmission housing — 4–5 lb ft
(5–7 N·m)
❑ Retarder temperature sensor fitting in retarder valve body — 15–20 lb ft
(22–27 N·m)
❑ Retarder main pressure tap fitting in transmission housing and in retarder
valve body — 4–5 lb ft (5–7 N·m)
• COOLER, AIR, AND VACUUM LINES
❑ Check for leaks
❑ Check for tightness of connections
❑ Check routing
• LINKAGE
❑ Shift selector
— Adjustment (at all positions)
— Ease of movement
— Neutral safety switch (start only in neutral)
— Shift tower (for freedom of operation)
❑ Mechanical modulator control
— Adjustment (proper shift points)
— Ease of operation
— Routing
❑ Parking brake
— Adjust for proper clearance
— Adjust for full apply
— Check for full release
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• DRIVELINE
❑ Check for proper indexing of universal joints
❑ Check for proper drive shaft angles
❑ Check driveline backlash
❑ Lubricate universals and slip-joints
• HYDRAULIC SYSTEM
❑ Recommended fluid (refer to Paragraph 1–6)
❑ Sufficient fluid in transmission (refer to Paragraph 1–4)
❑ Dipstick properly marked
❑ Fill cap tight
❑ Fill tube tight at pan
❑ Breather clean, free of restriction
❑ Filter differential pressure switch and alarm circuit
• POWER TAKEOFF
❑ Backlash properly established
❑ Controls connected and operative
❑ Properly coupled to driven equipment
❑ Lubrication line properly routed and connected
• INSTRUMENTS, ELECTRIC COMPONENTS
❑ Speedometer
❑ Fluid temperature gauge
❑ W iring and electrical connections, especially retarder or electric modulator
❑ Check neutral start switch
• MOUNTING
❑ No interference between engine/transmission components and frame on
acceleration
❑ Rubber mounts free and in good condition
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• MOUNTING (cont’d)
❑ Tail support preload correct
❑ Engine/transmission properly aligned
❑ Linkages and hoses do not restrain engine “roll” on acceleration
6–2. ROAD TEST AND VEHICLE OPERATION CHECKLIST
• NEUTRAL START
❑ Check the position of the operator’s selector lever in each drive
range and N (Neutral). The lever should align with the mark
indicating a range (or N (Neutral) or P (Park)) when the
transmission is in that range (or N (Neutral) or P (Park)).
❑ Check the neutral safety switch by trying to actuate the starter in every
selector position. The starter should operate only when the selector lever is
in N (Neutral) position or P (Park).
• INSTRUMENTS
❑ Check the instruments associated with the transmission. These include the
speedometer and the transmission oil temperature gauge.
• PARKING BRAKE
❑ Check application and release of the parking brake.
❑ Ensure the brake is not dragging or heating up while released.
❑ Ensure the brake is fully applied before the lever reaches full travel.
• POWER TAKEOFF (PTO)
❑ Check operation of the PTO. Refer to the Operator’s Manual
(OM1334EN) for general operating instructions, or to the vehicle
manufacturer’s specific instructions.
• NO-LOAD GOVERNED SPEED
❑ Check the no-load governed speed of the engine.
❑ Adjust the governor, if necessary, to meet the no-load governed speed
specified for your particular engine-transmission match (available from the
vehicle manufacturer).
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• SHIFT SEQUENCE
❑ Drive the vehicle and check the wide-open throttle upshift points. If
adjustment of the shift points is required, refer to the applicable AT
Service Manual. The shifts should occur at the following speeds:
— 1–2 upshift occurs within 400 rpm of full-load governed speed
— 2–3 upshift occurs within 300 rpm of full-load governed speed
— 3–4 upshift occurs within 200 rpm of full-load governed speed
• RETARDER
❑ Check that the retarder responds correctly to 50 percent or 100 percent
apply.
❑ Check that the retarder enable switch turns off the retarder.
❑ Check that retarder only applies at closed throttle.
❑ Check that low speed cutoff switch turns off the retarder in first range.
❑ Check that the retarder temperature indicator increases rapidly when the
retarder is applied.
❑ Check that the brake lights come on when the retarder is applied.
• TRANSMISSION FLUID
❑ Fluid level meets specification (transmission in N (Neutral) or
P (Park)).
❑ Check for leaks.
❑ Warm up transmission and perform a fluid level “hot” check (transmission
in N (Neutral) or P (Park) and vehicle on a level surface).
• OTHER CHECKS
❑ Stall check
❑ Shift quality
❑ Comments:__________________________________________________
____________________________________________________________
____________________________________________________________
____________________________________________________________
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SECTION
CUSTOMER
VII
SERVICE
7–1. OWNER ASSISTANCE
The satisfaction and good will of the owners of Allison transmissions are of primary
concern to Allison Transmission Division (ATD), its distributors, and their dealers.
As an owner of an Allison transmission, you have service locations throughout the
world that are eager to meet your parts and service needs with:
• Expert service by trained personnel
• Emergency service 24 hours a day in many areas
• Complete parts support
• Sales teams to help determine your requirements
• Product information and literature
Normally, any situation that arises in connection with the sale, operation, or service
of your transmission will be handled by the distributor or dealer in your area (check
the telephone directory for the Allison Transmission service outlet nearest you).
Reference the Sales and Service Directory (SA2229EN) for the current listing of
Allison Transmission authorized distributor and service dealers.
We recognize, however, that despite the best intentions of everyone concerned,
misunderstandings may occur. To further assure your complete satisfaction, we have
developed the following three-step procedure to be followed in the event a problem
has not been handled satisfactorily.
Step One — Discuss the problem with a member of management from the
distributorship or dealership. Frequently , complaints are the result of a breakdo wn
in communication and can quickly be resolved by a member of management. If you
have already discussed the problem with the Sales or Service Manager, contact the
General Manager. All ATD dealers are associated with an ATD distributor. If the
problem originates with a dealer, explain the matter to a management member of the
distributorship with whom the dealer has his service agreement. The dealer will
provide his ATD distributor’s name, address, and telephone number on request.
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Step T wo — When it appears the problem cannot be resolved readily at the
distributor level without additional assistance, contact the Allison Transmission
Regional Office responsible for the local distributor. You will be assisted by a
member of the Regional Service Manager’s staff, depending on the nature of your
problem.
For prompt assistance, please have the following information available.
• Name and location of authorized distributor or dealer
• Type and make of equipment
• Transmission model number, serial number, and assembly number (if
equipped with electronic controls, also provide the ECU assembly number)
• Transmission delivery date and accumulated miles and/or hours of operation
• Nature of problem
• Chronological summary of unit’s history
Step Three — If you contacted a regional office and you are still not satisfied,
present the entire matter to the Home Office by writing to the follo wing address
or calling the phone number below:
Manager Warranty Administration — PF9, Allison Transmission
P.O. Box 894, Indianapolis, Indiana 46206-0894
Phone: (317) 242-3538.
The inclusion of all pertinent information will assist the Home Office in expediting
the matter. If an additional review by the Home Office of all the facts involved
indicates that some further action can be taken, the Regional Office will be advised.
When contacting the Regional or Home Office, please keep in mind that ultimately
the problem will likely be resolved at the distributorship or dealership utilizing their
facilities, equipment, and personnel. Therefore, it is suggested the above steps be
followed in sequence when experiencing a problem.
Your purchase of an Allison Transmission product is greatly appreciated, and it is
our sincere desire to assure complete satisfaction.
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7–2. SERVICE LITERATURE
Additional service literature is available. This service literature pro vides
fully illustrated instructions for the operation, maintenance, service,
overhaul, and parts support of your transmission. To ensure that you get
maximum performance and service life from your unit, see your dealer
or distributor for the following publications. Check the telephone
directory for the Allison Transmission service outlet nearest you.
Table 7–1. Service Literature
Transmission
Series
AT 542 SM1241EN PC2126EN
AT 540, AT 543,
AT 545
Service
Manual
Parts
Catalog
SM1241EN PC1235EN
Technician’s
Guide
GN2055EN*
GN2123EN**
GN2055EN*
GN1948EN**
Operator’s
Manual
OM1334EN
OM1334EN
AT 1545 SM1241EN PC1235EN GN2055EN* OM1334EN
* Automatic Transmission Fluid
** Principles of Operation
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MT1321EN 199606 Printed in USA 199804www.allisontransmission.com
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