Mechanic’s Tips
MT(B) 600
Series Transmissions
MT1357EN
Tips
Allison Transmission
MT 640, MT 643, MTB 643(R),
MT 644, MT 647, MTB 647,
MT 650, MT 653DR, MTB 653DR,
MT 654CR, MTB 654CR
Division of General Motors Corporation
July, 1997
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:
etc., if not strictly observed, could result in damage to or destruction of
equipment.
NOTE:
A warning is used when an operating procedure, practice,
A caution is used when an operating procedure, practice,
A note is used when an operating procedure, practice, etc., is
essential to highlight.
Section I PREVENTIVE MAINTENANCE
1–1 Periodic Inspection and Care . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1–2 Importance of Proper Fluid Level . . . . . . . . . . . . . . . . . . . . . . . 1
1–3 Dipstick Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1–4 Fluid Check Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1–5 Keeping Fluid Clean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1–6 Recommended Automatic Transmission Fluid
and Viscosity Grade. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1–7 Fluid and Filter Change Intervals. . . . . . . . . . . . . . . . . . . . . . . . 6
1–8 Fluid and Filter Change Procedure . . . . . . . . . . . . . . . . . . . . . . 8
1–9 Fluid Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1–10 Auxiliary Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1–11 Breather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1–12 Transmission Stall Test and Neutral
Cool–Down Check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Section II REMOVING TRANSMISSION
2–1 Draining Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2–2 Disconnecting Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2–3 Uncoupling From Engine And Driveline. . . . . . . . . . . . . . . . . 16
2–4 Removing Mounting Bolts. . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2–5 Removing Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2–6 Repair Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Section III PREPARING TRANSMISSION FOR INSTALLATION
3–1 Checking Input Components . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3–2 Checking Torque Converter Position. . . . . . . . . . . . . . . . . . . . 20
3–3 Installing Parking Brake and Output Flange . . . . . . . . . . . . . . 21
3–4 Installing Shift Selector Lever . . . . . . . . . . . . . . . . . . . . . . . . . 22
3–5 Installing Power Takeoff (PTO). . . . . . . . . . . . . . . . . . . . . . . . 23
3–6 Installing Shift Modulation Control. . . . . . . . . . . . . . . . . . . . . 25
4–1 Checking Flexplate, Engine Features. . . . . . . . . . . . . . . . . . . . 28
4–2 Checking Chassis, Driveline . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4–3 Checking Cooler, Tubes, Hoses, Fittings. . . . . . . . . . . . . . . . . 33
4–4 Checking Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
4–5 Mounting Adapter or Spacer . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Section V INSTALLING TRANSMISSION INTO VEHICLE
5–1 Handling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5–2 Coupling to Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5–3 Mounting Output Retarder. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5–4 Installing Transmission Mounting Components . . . . . . . . . . . 36
5–5 Coupling to Driveline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5–6 Connecting Cooler, Vacuum Lines, Air Lines. . . . . . . . . . . . . 36
5–7 Connecting Shift Selector Control. . . . . . . . . . . . . . . . . . . . . . 37
5–8 Installing Vacuum or Air Modulator Control . . . . . . . . . . . . . 38
5–9 Installing, Adjusting Mechanical Modulator Control . . . . . . . 39
5–10 Connecting Power Takeoff Controls . . . . . . . . . . . . . . . . . . . . 40
5–11 Connecting Parking Brake Control . . . . . . . . . . . . . . . . . . . . . 40
5–12 Connecting Speedometer Drive . . . . . . . . . . . . . . . . . . . . . . . . 40
5–13 Filling the Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Section VI CHECKS AND ADJUSTMENT
6–1 Installation Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
6–2 Road Test and Vehicle Operation Checklist . . . . . . . . . . . . . . 44
Section VII CUSTOMER SERVICE
7–1 Owner Assistance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
7–2 Service Literature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
taining MT(B) 600 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-III® is a registered trademark of General Motors Corporation
Loctite® is a registered trademark of the Loctite Corporation
Teflon® is a registered trademark of the DuPont Corporation
Model MT 643 Transmission — Right-Front View
Model MT 653 Transmission — Right-Front View
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
•
Leaks in the vacuum or 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 and 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 level be maintained at all
times. If the fluid level is too low, the input pump will draw air into the
system and the converter and clutches will not receive an adequate
supply of fluid. If the level is too high, clutch rotation will aerate the
fluid, the transmission will overheat, and fluid may be expelled through
the breather or dipstick tube. Check the transmission fluid for changes in
markings for MT 600 Series transmissions. Figure 1–2 illustrates the marks in
relation to the transmission.
NOTE:
The ADD and FULL dimensions on earlier dipsticks coincide
with the HOT RUN band dimension on later dipsticks. If desired, the
dipstick on earlier models can be recalibrated to show HOT RUN and
REF FILL (COLD RUN).
CHECK IN NEUTRAL
AT IDLE
TRANSMISSION
OIL PAN
SPLITLINE
HOT RUN
(19.0 mm)
0.75"
REF
FILL
4.34 in.
OIL PAN
1.50"
(38.0 mm)
(45.7 mm)
CHECK IN NEUTRAL AT IDLE
0.75"
(19.0 mm)
HOT RUN
1.80"
1.50"
(38.0 mm)
REF
FILL
CHECK IN NEUTRAL AT IDLE
2.55"
(64.8 mm)
2.22"
(57.1 mm)
HOT RUN
0.75"
(19.0 mm)
1.50"
(38.0 mm)
5.10 in.
OIL PAN
Figure 1–1. Typical Dipstick Markings
7 in.
OIL PAN
V03240
FULL
ADD
0.75"
(19 mm)
1.50"
(38 mm)
2.22"
(57 mm)
2.55"
(65 mm)
TOP OF
OIL PAN
HOT RUN
REF FILL
MT 643 / 653
Figure 1–2. How Fluid Levels Are Established
V03241
1–4. FLUID CHECK PROCEDURE
WARNING:
sudden and unexpected vehicle movement, do not perform
maintenance or service procedures until you:
• Put the transmission in N (Neutral).
• Set the parking brake and service brakes, and make sure they are
properly engaged.
• Chock the wheels and take any other steps necessary to keep the
vehicle from moving.
CAUTION:
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.
To help avoid injury and property damage caused by
Dirt or foreign matter must not be permitted to enter the
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) 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 REF FILL (COLD RUN) band, the level is satisfactory for operating the
transmission until the fluid is hot enough to perform a HOT R UN check. If the
fluid level is not within the REF FILL (COLD RUN) band, add or drain fluid
as necessary to bring the level to the middle of the REF FILL (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) or converter-out temperature is
180–220°F (82–104°C).
•
Park the vehicle on a level surface and shift to N (Neutral). Set the parking
1–5. KEEPING FLUID CLEAN
CAUTION:
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.
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.
Containers or fillers that have been used to handle any
1–6. RECOMMENDED AUTOMATIC TRANSMISSION FLUID
AND VISCOSITY GRADE
RECOMMENDED AUTOMATIC TRANSMISSION FLUID AND
VISCOSITY GRADE — NON-MT 643R TRANSMISSIONS
Hydraulic fluids (oils) used in the transmission are important influences on
transmission performance, reliability, and durability.
•
The following transmission fluid and viscosity grades are recommended.
— DEXRON®-III fluids for standard duty, on-highway applications
— Type C-4 fluids (Allison approved SAE 10W or SAE 30) for severe duty
and off-highway applications
— Type C-4 SAE 30 for all applications where the ambient temperature is
consistently above 95°F (35°C)
— Type C-4 SAE 30 for dropboxes
•
Some DEXRON®-III fluids are also qualified as Type C-4 fluids. To
ensure the fluid is qualified for use in Allison transmissions, check for a
DEXRON®-III or 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
at ambient temperatures lower than those shown will require preheating with
auxiliary heating equipment or by running the vehicle with the transmission in
N
(Neutral) for a minimum of 20 minutes before attempting range operation.
RECOMMENDED AUT OMA TIC TRANSMISSION FLUID AND
VISCOSITY GRADE — MT 643R TRANSMISSIONS
•
Due to the added heat load from the input retarder, MT 643R transmissions
require special fluid considerations. The approved fluids list is more restricti ve
than for non-retarder MT 643R transmissions. Also, the fluid change interv als
are shorter than for non-retarder MT 643R transmissions.
•
Only high quality, hea vy duty diesel engine oils that are appro v ed Allison C-4
fluids with a viscosity of either SAE 30 or SAE 15W-40 are recommended for
use in MT 643R transmissions. For specific name brands, contact the local
Allison Transmission Regional Office.
•
Refer to Table 1–1 for minimum fluid temperatures at which the transmission
may be safely operated with various fluids. Operation at ambient temperatures
lower than those shown will require preheating with auxiliary heating
equipment or by running the vehicle with the transmission in N (Neutral) for a
minimum of 20 minutes before attempting range operation.
Table 1–1. Transmission Fluid Operating Temperature Requirements
Viscosity Grade
SAE 0W-20 (Arctic) –31 –35
DEXRON®-III
SAE 10W –4 –20
SAE 15W-40 5 –15
SAE 30 32 0
SAE 40 50 10
Ambient T emperatur e Below Which Preheat
Is Required
Fahrenheit Celsius
–22 –30
1–7. FLUID AND FILTER CHANGE INTERVALS
•
Fluid change intervals can be optimized by monitoring fluid oxidation
according to the tests and limits in the Fluid Contamination section of this
manual.
Table 1–2. Fluid and Filter Change Intervals
Transmission
Application
MT 600 Series
(On-Highway,
Non-MT 643R)
MT 643R After first 5000
MT 600 Series
(Off-Highway)
* Whichever occurs first.
** An Allison high-efficiency filter may be used until the Change Filter light indicates it is
contaminated or until it has been in use for 3 years, whichever occurs first. No mileage restrictions
apply.
Fluid Change
25,000 miles
(40 000 km)
or 12 months*
miles (8000 km)
then at 20,000
miles (32 000
km) or 12
months*
1000 hours
maximum or
12 months*
Internal Sump
Filter
Paper Filter:
25,000 miles
(40 000 km) or
12 months*
Stainless Steel
Screen:
At overhaul
Paper Filter:
At every other
fluid change
Stainless Steel
Screen:
At overhaul
Paper Filter:
1000 hours
maximum or 12
months*
Stainless Steel
Screen:
At overhaul
Governor
Filter
25,000 miles
(40 000 km)
or 12 months*
20,000 miles
(32 000 km) or
12 months*
1000 hours
maximum or
12 months*
External
Auxiliary
Filters**
After first 5000
miles (8 000 km)
and at normal fluid
change intervals,
thereafter*
After first 5000
miles (8000 km)
then at each fluid
change, thereafter
After first 500
hours and at
normal oil change
intervals,
thereafter*
A stainless steel screen sump filter is available for all later model MT 600 Series
transmissions except the MT(B) 654CR. This filter does not require replacement at
the regular fluid change intervals, but transmissions equipped with a sump screen
must have an auxiliary filter in the external transmission cooling circuit. Refer to
Service Information Letter (SIL) 6-TR-96 (latest revision).
•
The transmission should be at operating temperature to assist
draining.
•
Remove the drain plug from the pan. In earlier models without a drain plug,
remove the fill tube.
•
Examine the drained fluid for evidence of contamination (refer to
Paragraph 1–9).
•
Remove the pan and gasket. Discard the gasket. Remove the washer head
screw that retains the filter. Remove the filter and filter tube. Discard the filter
(if being replaced) and the filter tube sealring. Clean the pan.
NOTE:
Transmissions equipped with a stainless steel screen sump
filter or a 7.0 inch (180 mm) pan do not require pan removal. Refer to
Service Manual SM1317EN or SM1546EN for specific procedures.
•
Install a new governor feed filter at the rear of the transmission. Refer to the
latest revision of Service Manual SM1317EN or SM1546EN for the exact
location.
•
Install a new filter if required. Insert a new sealring onto the filter tube. Install
the filter tube and filter into the main housing. Install the pan and pan gasket if
removed. 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
the fill tube was removed (earlier models), install the fill tube and tighten the
fill tube fitting in the pan boss to the torque shown in Paragraph 6–1.
•
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 Table 1–3.)
•
The refill amount is less than the initial fill because some of the fluid remains
4.3 inches (110 mm) 12 U.S. qt. (11 liters)*
5.1 inches (130 mm) 15 U.S. qt. (14 liters)*
7.0 inches (180 mm) 17 U.S. qt. (16 liters)*
* The amount of transmission fluid shown does not include the amount required to fill the
external circuits.
1–9. FLUID CONTAMINATION
a.
Examine at Fluid Change
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.
Metal Particles
b.
CAUTION:
If excessive metal contamination has occurred,
replacement of the cooler and inspection of all bearings within the
transmission is recommended.
Metal particles in the fluid or on the magnetic drain plug (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 must 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
one fluid analysis firm as results from various firms cannot be accurately compared.
Refer to the Technicians’ Guide for Automatic T ransmission Fluid (GN2055EN) for
additional information.
To optimize transmission protection, the following is the minimum series of tests
required to properly monitor the condition of the transmission and transmission
fluid/filter system.
•
Wear Metals (ppm): Fe, Cu, Pb, Al
•
Additive and Contaminant Metals (ppm): Ba, B, Ca, Mg, P, Si, Na, Zn
•
Non-metal Contaminants: Fuel (% vol), Soot, (% wt), Water (% vol)
•
Viscosity (cSt) at 40˚C (ASTM D445)
•
Viscosity (cSt) at 100˚C (ASTM D445)
•
TAN (Total Acid Number) (ASTM D664)
•
Particle Counts (particles/ml) at >5, >10, >20, >30, and >40 microns
ppm = parts per million cSt = centiStokes ml = milliliter
To optimize fluid change intervals, monitor fluid oxidation per the tests and limits
shown in Table 1–4. A fluid is considered suitable for use if it meets all four limits
listed in the table, regardless of color or odor. If one of the limits is exceeded,
however, the fluid in the subject transmission should be sampled again immediately
to verify the exceeded limit. If verified, the fluid should be changed regardless of
time or mileage.
Table 1–4. Fluid Oxidation Measurement Limits
Condition Limit
Viscosity ± 25% Change From New Fluid
Carbonyl Absorbance
Total Acid Number (TAN)
Solids
* Carbonyl absorbance units/cm
** mg of KOH required to neutralize a g of fluid
+ 30* Change From New Fluid
+ 3.0** Change From New Fluid
2% By Volume Maximum
1–10. AUXILIARY FILTER
•
For models without a retarder, install an auxiliary filter in the cooler-out line
(between the cooler and transmission) if such a filter does not already exist.
•
For models with an output retarder, replace the main cooler and install an
auxiliary filter in the line between the retarder control valve and the lube port
(right side of the transmission).
•
For models with an input retarder, install an auxiliary filter in the secondary
cooler circuit.
FILTER
CAUTION:
DO NOT install an auxiliary filter in the MT 643R
primary cooler circuit. This reduces retarder effectiveness. An
auxiliary filter in the secondary cooler circuit is sufficient.
Water Flow
Oil Flow
SECONDARY
COOLER
PRIMARY
COOLER
(TYPICAL)
L03879.02
The auxiliary filter should have a 40-micron or finer filter element and a maximum
filter pressure drop of 3 psi (21 kPa) at 8 gpm (30 liters/minute) at 180˚F (82˚C). The
maximum external circuit pressure drop at normal operating temperature must not
exceed 23 psi (159 kPa) for the MT(B) 640, 643, 650, 653 and 50 psi (345 kPa) for
the MT(B) 644, 647, 654CR at 2000 rpm in N (Neutral).
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
Fram HP 1-2**
Purolator OF-15C-1
Purolator PER-20-10
* High-efficiency filter and element are av ailable from your authorized Allison distributor .
Refer to SIL 12-TR-93 (latest revision).
**Use with MT 640, 643, 650, 653 only
Allison 29510922*
PF 897
PF 141
HP 1
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
manufacturer’s data from the engine manufacturer or from your
equipment dealer or distributor.
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: To help avoid injury and property damage caused by
sudden and unexpected vehicle movement, do not begin a stationary
stall test until you:
• Put the transmission in N (Neutral).
• Set the parking brake and service brakes, and make sure they are
properly engaged.
• Chock the wheels and take any other steps necessary to keep the
vehicle from moving.
• Warn people to keep clear of the vehicle and its path.
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 in
N (Neutral) 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.)
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). Increase engine speed to cool the
torque converter.
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), 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 conv erter f ailure.
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.
TRANSMISSION
2–1. DRAINING TRANSMISSION
• Remove the drain plug from the pan. For earlier models, disconnect the
transmission fill tube from the pan. 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
II
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 air hose from the air modulator or air-operated retarder valve
(if used). Remove the air modulator and plug the opening in the transmission.
• Disconnect any electrical leads to sensors or other equipment on the
transmission.
2–3. UNCOUPLING FROM ENGINE AND 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.
• Figures 2–1 and 2–2 show typical methods of coupling the engine and
transmission. Remove the driv e cover nuts (Figure 2–1) or dri ve bolts (Figures
2–1, 2–2).
FLYWHEEL
HOUSING
FLEXPLATE/RING
GEAR ASSEMBLY
DRIVE COVER
NUTS
(ACCESSIBLE
FROM FRONT)
CRANKSHAFT
HUB ADAPTER
CRANKSHAFT
CRANKSHAFT
CENTERLINE
TRANSMISSION
HOUSING
WEAR
PLATE
DRIVE
COVER
FLYWHEEL/RING
GEAR ASSEMBLY
DRIVE BOLTS
(ACCESSIBLE
FROM BOTTOM)
DRIVE
COVER
NUTS
CRANKSHAFT
CRANKSHAFT
CENTERLINE
FLYWHEEL
HOUSING
SAE #2
TRANSMISSION
Figure 2–1. Typical Coupling Methods — MT(B) 640, 643, 650, 653
(TC 300 Converter)
HOUSING
FLEXPLATE
ADAPTER
FLEXPLATE
WEAR
PLATE
DRIVE
COVER
V03242
ADAPTER
SAE #2 TO 1
BOLT (12)
CRANKSHAFT
HUB ADAPTER
CRANKSHAFT
STARTER
RING GEAR
FLEXPLATE
ENGINE
CRANKSHAFT
STARTER
RING GEAR
BOLT (12)
FLEXPLATE
ENGINE
FLYWHEEL
HOUSING
SAE #2
BOLT (12)
CRANKSHAFT
CENTERLINE
TORQUE
CONVERTER PUMP
WEAR PLATE
DRIVE COVER
BOLT (6)
LOCKWASHER (10)
SPACER
SAE #2
TORQUE
CONVERTER
PUMP
CRANKSHAFT
HUB ADAPTER
WEAR PLATE
DRIVE COVER
BOLT (6)
TRANSMISSION
HOUSING
BOLT (10)
TRANSMISSION
HOUSING
SPACER
SOCKET HEAD
SCREW (2)
SAE #2
Socket head screws
must be located at
holes nearest to
horizontal centerline
CRANKSHAFT
CENTERLINE
V03243
• 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.
Refer to Figures 2–1 and 2–2 for bolts and nuts within the flywheel housing.
NOTE: To remove the transmission from the flywheel housing, do the
following.
• When an adapter is used to adapt the transmission to a larger engine
flywheel housing (Figure 2–2), remove only the transmission-toadapter bolts.
• When a spacer is used, the transmission is fastened to the flywheel
housing in one of two ways.
— Remove the ten bolts that pass through the spacer and hold the
transmission to the flywheel housing. To remove the spacer,
remove the two bolts that hold the spacer to the flywheel
housing.
— Remove the ten bolts and two studs that pass through the spacer
and hold the transmission to the flywheel housing.
2–5. REMOVING TRANSMISSION
CAUTION: Do not pull the transmission away from the torque
converter assembly. The torque converter drive co ver must be entirely
free of any restraint by the flexplate driv e or crankshaft pilot when the
transmission separates from the engine.
CAUTION: If the spacer is not independently bolted to the engine
(Figure 2–2), prevent the spacer from falling during transmission
removal.
• 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.
2–6. REPAIR INSTRUCTIONS
• Refer to the applicable Allison Transmission Service Manual SM1317EN or
SM1546EN (latest revision) to repair the transmission.
RETAINING STRAP
H00014
Figure 2–3. Location of Torque Converter Retaining Strap
III
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
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:
— MT 640, 643, 650, 653: 2.854–3.014 inch (72.49–76.55 mm)
— MT 644, 647, 654CR: 4.336–4.486 inch (110.14–113.94 mm)
• A measurement outside these dimensions indicates the torque converter is not
installed properly. Refer to the applicable Allison Transmission Service
Manual SM1317EN or SM1546EN (latest revision).
Measure over
spacer and
retainer
HOUSING
HOUSING
SPACER OR
SPACER AND
RETAINER
FLYWHEEL
MT 640, 643, 650, 653 MT 644, 647, 654CR
Figure 3–1. Converter Position Measurements
• If not previously installed (on transmissions coupled as in Figure 2–1), install
the flexplate adapter over the spacers and retainers on the drive cover studs.
Secure the adapter with six nuts, tightened to 34–40 lb ft (46–54 N·m).
NOTE: The nuts must be self-locking and capable of producing a
tensile load of 8000 lbs (36 kN). A nut that meets these requirements
is Allison P/N 23014107.
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 SM1317EN or SM1546EN (latest
revision).
• Lubricate the oil seal with petrolatum or transmission fluid.
• Check the oil drip tube below the rear cover to ensure it is clean and
unobstructed.
• Check the output flange or yoke for damage or wear. Check the oil seal
V03244
• 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.
• The MT 640, 643, or 644, 647 output flange is retained by a 1⁄2-20 x 11⁄2 inch
bolt and a 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 (latest
revision). The torque value is the same for both bolts.
• The MT(B) 650, 653, or 654CR output flange is retained by a self-locking
nut. Clean the threads of the nut and the output shaft. Apply molybdenum
disulfide grease to the output shaft and nut threads. Install the nut on the
output shaft. Tighten the nut to 600–800 lb ft (813–1085 N·m).
NOTE: The self-locking ability of the nut is reduced with each usage.
Each time the nut is reused, scribe a deep mark on one of the flats on
the nut. Discard the nut after it has been reused five times.
3–4. 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.
• 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
The lever must be seated fully against the shaft shoulder.
SELECTOR
LEVER
V03254
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.
• Early model transmissions have a 6/8 pitch driv e gear while later models ha ve
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.
• Determining PTO Backlash
engagement or whining gears indicate a tight fit and require the addition
of one or more gaskets.
NOTE: Do not remove all gaskets from beneath the PTO housing.
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).
BASE PLATE
GAUGE PIN
MEASUREMENT
PTO PAD
HOLD DOWN
BOLT
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
TRANSMISSION
MAIN CASE
J 34814
PTO DRIVE
GEAR
V02394
One–0.030 in. Gasket (one 0.76 mm Gasket)
Two–0.030 in. Gaskets (two 0.76 mm Gaskets)
3–6. INSTALLING SHIFT MODULATION CONTROL
• Install the modulation control after the transmission is put into the vehicle.
Refer to Paragraphs 5–8 and 5–9.
PTO DRIVE
GEAR
PTO MOUNTING
PAD
SNAPRING
H00388.02
Figure 3–4. View at PTO Opening
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 2410501058 where the oil pan boss length was
changed from 0.575 to 0.675 inch. Reference SIL 30-TR-94.
• Ensure the drain plug is in place and tightened to 15–20 lb ft (20–27 N·m).
3–8. INSTALLING NEUTRAL START AND REVERSE
SIGNAL SWITCHES
NOTE: The type and location of the Neutral Start Switch is optional.
A functional Neutral Start Switch is required to avoid starting the
engine in range.
• Connect any wiring required for sensors, signals, switches, or other electrical
components.
• Install the Neutral Start Switch (if so equipped) into the tapped opening above
the selector shaft (Figure 3–5). 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
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.
®
pipe
NEUTRAL START
SWITCH LOCATION
SELECTOR
LEVER SHAFT
ACTUATOR
ROD
V03245
switch. Install the switch into the 1⁄8 inch pipe-threaded opening near the
nameplate, at the right side of the transmission. Tighten the switch to 4–5 lb ft
(5–7 N·m). Connect the wire leads.
NOTE: An enhanced reverse pressure switch P/N 29503665 became
available in Nov ember 1994. The improv ed switch is stamped with the
3-digit code 484. See SIL 7-TR-95.
3–9. CHECKING BREATHER
Ensure the breather is clean and free of obstructions. Also, the breather cap must be
loose and free to rattle. Figure 3–6 shows the 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
Figure 3–6. Breather Configurations
V02884
IV
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. Refer to SIL 60-TR-81 (latest revision).
1
2
3
Figure 4–1. Tooling Used to Determine the Adaptation
Measurements of an MT(B) 600 Series Transmission
4
H00389.01
Tool Description Kent-Moore No.
1. 24 inch (610 mm) Vernier caliper* J 26900-25
2. 1.5–2 inch (38–50 mm) telescoping gauge J 26900-23
3. 1–2 inch (25–50 mm) outside and inside micrometers J 26900-2
4. Dial indicator and attachments (base and posts) J 5959-01
NI. 0–6 inch (0–150 mm) depth micrometer set Not offered
* The 24 inch caliper can also be used as a precision straight edge.
NI = Not illustrated.
Flywheel
Housing
Bore Diameter 17.625–17.630 in.
(447.68–447.81 mm)
Bore Eccentricity*
MT(B) 640, 643, 650,
653 S/N 33458 and
later or models updated
with converter pump
hub bushing P/N
6881926 or roller
bearing P/N 7455739;
all MT(B) 644, 647,
654CR
MT(B) 640, 643, 650,
653 prior to S/N 33458
Face Squareness*
MT(B) 640, 643, 650,
653 S/N 33458 and
later or models updated
with converter pump
hub bushing P/N
6881926 or roller
bearing P/N 7455739;
all MT(B) 644, 647,
654CR
MT(B) 640, 643, 650,
653 prior to S/N 33458
* Limits are for installed engines.
0.020 in. (0.51 mm) T.I.R.
0.008 in. (0.20 mm) T.I.R.
0.020 in. (0.51 mm) T.I.R.
0.008 in. (0.20 mm) T.I.R.
Crankshaft Hub
and/or Adapter
Crankshaft Hub or Hub
Adapter Pilot Diameter
Converter Pilot Hub
Diameter
1.703–1.705 in.
(43.26–43.31 mm)
1.699–1.702 in.
(43.16–43.23 mm)
Face Squareness 0.0005 in. (0.013 mm) T.I.R.**
Pilot Eccentricity†
MT(B) 640, 643, 650,
653 S/N 33458 and
later or models updated
with converter pump
hub bushing P/N
6881926 or roller
bearing P/N 7455739;
all MT(B) 644, 647,
654CR
MT(B) 640, 643, 650,
653 prior to S/N 33458
Flexplate Check for Radial
Cracks
Check for Elongated
Mounting Holes
Check for An y Signs of
Distress and/or Wear
Mounted
Flexplate (refer
to Figure 4–2)
Converter Axial
Location
MT(B) 640, 643, 650,
653 Series
MT(B) 644, 647,
654CR Series
Flatness
Formed Plates
Flat Plates 0.157 in. (3.99 mm)
** T.I.R. per inch of diameter.
0.010 in. (0.25 mm) T.I.R.
0.005 in. (0.13 mm)
None permitted
None permitted
None permitted
2.854–3.014 in.
(72.49–76.56 mm)
4.336–4.486 in.
(110.14–113.94 mm)
†† 0.039 in. (0.99 mm)
FLEXPLATE/RING
GEAR ASSEMBLY
CRANKSHAFT
CRANKSHAFT
HUB ADAPTER
MT 644, 647, 654CR
WEAR PLATE
Figure 4–2. Flexplate Location Dimensions
3.014 in. (76.55 mm)
4.336 in. (110.14 mm)
4.486 in. (113.94 mm)
V03246
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 transmission 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.
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.
• Cooler connecting lines –– clean and flush; inspect for deterioration, leaks,
faulty connectors, kinks. Minimum tube size required for cooler circuit is
0.625 inch (15.9 mm) or No. 12 hose size. 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.”
• 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 movement, frayed or
kinked cables, lack of lubrication, worn rod ends or clevis pins, damaged
threads, or improper routing.
• Air modulator control — inadequate freedom of movement, incorrect
pressure calibration (engine throttle must go to full throttle position when
treadle is fully depressed), damaged hoses or fittings, or improper routing.
NOTE: Air pressure input required for pneumatic control is
55–65 psi (379–448 kPa).
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.
4–5. MOUNTING ADAPTER OR SPACER
• When a mounting adapter (Figure 2–2) is used to adapt the transmission to an
SAE 1 flywheel housing, install the adapter onto the engine. Retain it with the
twelve SAE Grade 8 bolts and lockwashers supplied with the vehicle. Tighten
the bolts to 54–65 lb ft (73–88 N·m).
• When a mounting spacer is used (Figure 2–2), install the spacer onto the
engine. Retain with the two bolts and washers supplied with the vehicle.
CAUTION: Bolt heads must be below the rear surface of the spacer
before installing the transmission.
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 converter drive
studs will enter the bolt holes in the flexplate (Figure 2–1), or so that
the drive bolts can be installed (Figures 2–1 and 2–2).
NOTE: When the starter ring gear is separate from the flexplate
(Figure 2–2), the ring gear must also be aligned.
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 flexplate center bore and the drive studs into the flexplate
outer holes.
• Engage 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 SAE Grade 8 bolts that secure the transmission housing to
the engine flywheel housing or adapter. Tighten the bolts to 36–43 lb ft
• Tighten the drive cover nuts to 34–40 lb ft (46–54 N·m).
• Tighten the drive cover bolts to 41–49 lb ft (56–66 N·m).
• Check crankshaft end play against engine manufacturer’s specifications.
5–3. MOUNTING OUTPUT RETARDER
Transmissions with the integral output retarder require special attention when
mounting. The additional weight of the retarder makes it necessary to support the
transmission behind the engine using the rear support pads on the top of the retarder
housing or the vertical pads on the rear face of the retarder case. The converter
housing side-mount pads cannot be used with MTB 653 direct-mount units. Only
remote-mount units and MTB 643 direct-mount units may be installed using the
side-mount pad on the converter housing with a rear support.
5–4. INSTALLING TRANSMISSION MOUNTING COMPONENTS
CAUTION:
• Bolts must not penetrate the two rear holes of the converter side
mounting pad more than 1.125 inch (28.6 mm). Tighten mounting
pad bolts to 81–97 lb ft (110–132 N·m).
• Bolts must not penetrate the two front holes of the converter side
mounting pad more than 1.25 inch (31.8 mm) to avoid interference
with the converter. Tighten mounting pad bolts to 81–97 lb ft
(110–132 N·m).
• Install all bolts, washers, cross-members, supports, and isolators required to
support the transmission in the vehicle frame.
5–5. 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.
5–6. CONNECTING COOLER, VACUUM LINES, AIR LINES
• If a vacuum modulator is used, connect the vacuum modulator line at the
intake manifold.
• If an air modulator is used, connect the air line from the junction of the
accelerator-to-engine fuel control air line to the air modulator control. Keep
the line away from exhaust pipes and components that cause chafing. Avoid
kinks and sharp bends.
5–7. CONNECTING SHIFT SELECTOR CONTROL
• Place the operator’s shift selector control at the N (Neutral) position. Place the
selector lever (on the transmission) in the N (Neutral) position (Figure 5–1).
• 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.
1
2
1–2–3–4
1
1–2
2–3–4
1–2–3
1–2–3–4
2–3–4–5
1–2–3–4–5
R
N
R
N
N
MT 640, 643, 644, 647
MT 650, 653
MT 654CR
R
V03247
1
1–2
1–2–3
Figure 5–1. Shift Selector Positions
• 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 5⁄16-18 x 3⁄4 inch bolt.
(Earlier models use a 5⁄16-18 x 9⁄16 inch bolt.) Tighten the bolt to 10–16 lb ft
(14–22 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.
HOSE
10°
Figure 5–2. Proper Relation of Vacuum Hose to Modulator Control
VACUUM MODULATOR
V03248
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 registers with the hole in
the throttle linkage lever and the connecting pin can be freely inserted. With the
pin removed, rotate the clevis or rod end one additional turn counter -clockwise
(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 achie ve 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 trav el 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 lever marked PUSH on one side and PULL on
the opposite side. When the modulator control cover is remo ved, the word
PUSH or PULL can be seen and indicates how the device is assembled.
• Conversion 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.
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. Tighten
the body in the transmission rear cover 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 the same as for the driven gear body). Do not
operate transmission with the plastic shipping plug in this hole.
• Install the speedometer drive cable onto the driv en gear assembly. Tighten the
cable nut to 50–55 lb in. (5.6–6.2 N·m). Avoid sharp bends in the cable. All
bends must have a radius of at least 6 inches (152 mm) and no more than one
90 degree bend is allowed. The torque required to drive the cable and all
associated equipment should not exceed 25 oz in. (0.17 N·m).
ADJUSTMENTS
6–1. INSTALLATION CHECKLIST
• PROPER TORQUE
❑ Flexplate to drive cover bolts — 41–49 lb ft (56–66 N·m)
❑ Flexplate/adapter to drive cover nuts — 34–40 lb ft (46–54 N·m)
❑ Transmission-to-frame mounting bolts
— Models without retarder — 164–192 lb ft (222–260 N·m)
— Models with retarder — 67–81 lb ft (90–110 N·m)
❑ Converter side mount bolts — 81–97 lb ft (110–132 N·m)
❑ Output flange retaining bolt (MT 640, 643, 644, 647) — 102–121 lb ft
(138–164 N·m)
❑ Output flange nut (MT 650, 653, 654CR) — 600–800 lb ft (813–1085 N·m)
❑ Companion flange or universal joints bolts*
❑ Converter housing adapter to engine housing — 54–65 lb ft (73–88 N·m)
❑ Transmission housing to engine housing or adapter — 36–43 lb ft
(49–58 N·m)
VI
❑ 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)
❑ Bellcrank and cable support brackets to transmission — 42–50 lb ft
(57–68 N·m)
❑ Cooler lines to transmission — 25–34 lb ft (34–47 N·m)
❑ Temperature sensor plug or temperature sending unit — 16–20 lb ft
(22–27 N·m)
(61–68 N·m)
❑ 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)
• 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
• DRIVELINE
❑ Check for proper indexing of universal joints
❑ Check for proper drive shaft angles
❑ Sufficient fluid in transmission
❑ Dipstick properly marked
❑ Fill cap tight
❑ Fill tube tight at pan
❑ Vent hole in fill tube
❑ 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
❑ Oil 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
❑ Tail support preload correct
❑ Engine/transmission properly aligned
❑ 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)) when the transmission is in
that range (or N (Neutral)).
❑ 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.
• INSTRUMENTS
❑ Check the instruments associated with the transmission. These include the
speedometer and the transmission fluid temperature gauge.
• PARKING BRAKE
❑ Check application and release of the parking brake. (Retarder models do
not use a transmission-mounted 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).
upshifts, except the 1–2 shift for the MT 640, 643, or 654CR and the 2–3
shift for the MT 650, 653. The latter two shifts should occur at full-load
governed speed less 600 rpm. The 1–2 shift in MT 650, 653 models is a
manual shift and not subject to adjustment.
❑ Drive the vehicle and check the wide-open throttle upshift points. If
adjustment of the shift points is required, refer to the applicable MT
Service Manual.
• RETARDER
❑ Check that the retarder responds correctly.
❑ Check that the retarder enable switch turns off the retarder.
❑ Check that retarder only applies at closed throttle.
❑ 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)).
❑ Check for leaks.
❑ Warm up transmission and perform a fluid level “hot” check (transmission
in N (Neutral) and vehicle on a level surface).
• OTHER CHECKS
❑ Stall check
❑ Shift quality
❑ Comments:__________________________________________________
____________________________________________________________
____________________________________________________________
____________________________________________________________
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 distributors 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
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) 242-2052
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.
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
Literature Title
MT(B) 640, 643,
650, 653DR
MT(B) 644, 647,
654CR
Service Manual SM1317EN SM1546EN
Parts Catalog PC1316EN PC1551EN
Operator’s Manual OM1334EN OM1334EN
Troubleshooting Manual TS1838EN TS1838EN
Automatic Transmission Fluid
GN2055EN GN2055EN
Technician’s Guide
Output Retarder Inspection/
GN2009EN GN2009EN
Analysis
MT1357EN 199707 Printed in U.S.A. 199907
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