
ASSEMBLY
(1) Install input shaft-to-clutch retainer snap ring
(Fig. 133) (Fig. 134) (Fig. 132).
Fig. 132 Rear Clutch Assembly
1 - SNAP RING (SELECT) 6 - CLUTCH RETAINER 11 - SNAP RING (WAVE)
2 - REACTION PLATE 7 - INPUT SHAFT 12 - SEAL
3 - CLUTCH DISC 8 - SNAP RING 13 - SEAL
4 - CLUTCH PLATE 9 - PISTON
5 - REACTION PLATE 10 - SPRING
RS31TH AUTOMATIC TRANSAXLE21-89
CLUTCH - REAR (Continued)
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(2) Install rear clutch piston, belleville spring and
waved snap ring (Fig. 135). Install snap ring using a
suitable screwdriver (Fig. 136).
Fig. 133 Install Input Shaft Snap Ring
1 - INPUT SHAFT
2 - REAR CLUTCH RETAINER
3 - SNAP RING PLIERS
4 - SNAP RING
Fig. 134 Input Shaft Snap Ring
1 - INPUT SHAFT
2 - REAR CLUTCH RETAINER
3 - SNAP RING
Fig. 135 Rear Clutch Piston and Piston Spring
1 - INPUT SHAFT
2 - REAR CLUTCH RETAINER
3 - PISTON SPRING
4 - WAVED SNAP RING
5 - PISTON
6 - PISTON SEALS
Fig. 136 Piston Spring Waved Snap Ring
1 - REAR CLUTCH RETAINER
2 - PISTON SPRING
3 - SCREWDRIVER
4 - WAVED SNAP RING
21 - 90 31TH AUTOMATIC TRANSAXLERS
CLUTCH - REAR (Continued)
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(3) Install rear clutch pack (Fig. 137).
(4) Install snap ring using a suitable screwdriver
(Fig. 138).
(5) Using feeler gauges, measure rear clutch clear-
ance (Fig. 139).Rear clutch clearance should be
within 0.71-1.10 mm (0.028-0.043 in.).
FINAL DRIVE
DISASSEMBLY
NOTE: The differential is serviced as an assembly.
Service is limited to bearing cups and cones. Any
other failure must be repaired by differential assem-
bly and transfer shaft replacement.
(1) Remove transfer shaft.
(2) Measure differential bearing turning torque.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 31TH/BEARINGS - ADJUSTMENTS)
(3) Remove adapter plate seal.
(4) Remove differential cover-to-transaxle case
bolts (Fig. 140).
Fig. 137 Rear Clutch (4-Disc Shown)
1 - REAR CLUTCH RETAINER
2 - CLUTCH PLATES
3 - THICK STEEL PLATE
4 - SNAP RING (SELECTIVE)
5 - DRIVING DISCS
6 - PRESSURE PLATE
Fig. 138 Rear Clutch Outer Snap Ring
1 - SCREWDRIVER
2 - SNAP RING
3 - REAR CLUTCH ASSEMBLY
Fig. 139 Measuring Rear Clutch Plate Clearance
1 - REAR CLUTCH ASSEMBLY
2 - FEELER GAUGE
3 - SELECTIVE SNAP RING
Fig. 140 Differential Cover Bolts
1 - DIFFERENTIAL COVER
2 - DIFFERENTIAL COVER BOLT
RS31TH AUTOMATIC TRANSAXLE21-91
CLUTCH - REAR (Continued)
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(14) Remove differential bearing cone (Fig. 149).
(15) Remove bearing retainer bearing cup using
Tool 6062A (Fig. 150) (Fig. 151). Remove shim and oil
baffle.
ASSEMBLY
NOTE: The differential is serviced as an assembly.
Service is limited to bearing cups and cones. Any
other failure must be repaired by differential assem-
bly and transfer shaft replacement.(1) Install shim and bearing cup using Tool 5052
and driver handle C-4171 (Fig. 152). Install bearing
cup into extension housing using Tool 6536 and
driver handle C-4171.
Fig. 149 Remove Differential Bearing Cone
1 - SPECIAL TOOL 5048
2 - RING GEAR
Fig. 150 Position Bearing Cup Remover Tool in
Retainer
1 - SPECIAL TOOL 6062A
2 - DIFFERENTIAL BEARING RETAINER
Fig. 151 Remove Bearing Cup using 6062A
1 - SPECIAL TOOL 6062A
2 - DIFFERENTIAL BEARING RETAINER
Fig. 152 Bearing Retainer Bearing Cup Installation
1 - SPECIAL TOOL C-4171
2 - SPECIAL TOOL 5052
3 - DIFFERENTIAL BEARING RETAINER
21 - 94 31TH AUTOMATIC TRANSAXLERS
FINAL DRIVE (Continued)
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(11) Install adapter plate axle seal using Tool
L-4520 (inverted), and driver handle C-4171.
(12) Check differential turning torque. (Refer to 21
- TRANSMISSION/TRANSAXLE/AUTOMATIC -
31TH/BEARINGS - ADJUSTMENTS)
(13) Apply an 1/8º bead of MopartSilicone Rubber
Adhesive Sealant to the differential cover (Fig. 161).
(14) Install differential cover-to-transaxle case
bolts and torque to 19 N´m (165 in. lbs.) torque (Fig.
162).
(15) Install transfer shaft and related components.ADJUSTMENTS
ADJUSTMENT - DIFFERENTIAL BEARING
NOTE: Transfer shaft MUST be removed from trans-
axle to obtain an accurate differential turning torque
measurement.
Differential turning torque should be measured
and adjusted during any transaxle or differential
teardown/assembly, or if any of the following parts
are replaced:
²Transaxle case
²Differential carrier
²Differential bearing retainer
²Extension housing
²Differential bearing cups and cones
(1) Position the transaxle assembly vertically on
the support stand, differential bearing retainer side
up.
(2) Install Tool L-4436A into the differential and
onto the pinion mate shaft (Fig. 163).
(3) Rotate the differential at least one full revolu-
tion to ensure the tapered roller bearings are fully
seated.
Fig. 161 Install Differential Cover
1 - GOVERNOR PRESSURE PLUG
2 - DIFFERENTIAL COVER
3 - 1/8 INCH BEAD OF R T V SEALANT
4 - DIFFERENTIAL ASSEMBLY
Fig. 162 Differential Cover Bolts
1 - DIFFERENTIAL COVER
2 - DIFFERENTIAL COVER BOLT
Fig. 163 Tool L-4436 and Torque Wrench
1 - SPECIAL TOOL L-4436±A
2 - TORQUE WRENCH
3 - DIFFERENTIAL BEARING RETAINER
RS31TH AUTOMATIC TRANSAXLE21-97
FINAL DRIVE (Continued)
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ADJUSTMENTS
GEARSHIFT CABLE ADJUSTMENT
Lift and rotate the gearshift hand lever into the
park (P) gate position and remove the ignition key.
This confirms the shift lever is in the gated park (P)
position.
After confirming the park gate position, turn the
ignition switch . If the starter will operate, the park
gate position is correct. Move the shift lever into the
neutral (N) position. If the starter will operate in this
position, the linkage is properly adjusted. If the
starter fails to operate in either position, linkage
adjustment is required.
(1) Park the vehicle on level ground and set the
parking brake.
(2) Place the gearshift lever in park (P) gate posi-
tion and remove key.
(3) Loosen the cable adjustment screw at the
transaxle operating lever (Fig. 181).
(4) Pull the transaxle operating lever fully forward
to the park detent position.
(5) Release the park brake, then rock the vehicle
to assure it is in park lock. Reset the park brake.
(6) Tighten the cable adjustment screw to 8 N´m
(70 in. lbs.). Gearshift cable should now be properly
adjusted.
(7) Verify PRNDL indicator still displays the corre-
sponding gear completely. If not, readjustment of
PRNDL may be required.
(8) Check adjustment by using the preceding pro-
cedure.
GOVERNOR
DESCRIPTION
The governor assembly is fastened to the transaxle
transfer shaft. It consists of a governor body, weight,
valve, and shaft.
OPERATION
The governor meters hydraulic pressure, and this
metered pressure is used to signal the transmission
when it is time for a shift to occur. It does this by
balancing governor pressure on one side of a shift
valve, and throttle pressure on the other. When gov-
ernor pressure increases far enough to overcome the
throttle pressure on the valve, a shift occurs.
With the gearshift selector in a forward driving
range, line pressure flows from the manual valve and
down to the governor valve. When the output shaft
starts to rotate with vehicle motion, the governor
weight assembly will start to move outward due to
centrifugal force. As the weight is moved outward, it
will pull the valve with it until the land of the valve
uncovers the line pressure port. As the port begins to
become uncovered, governor pressure is metered. As
the vehicle's speed continues to increase, the weight
assembly will be at a point at which governor pres-
sure is acting on the left side of the reaction area of
the valve. This produces sufficient force to compress
the spring and allow the outer weight to move out
against the outer governor body retaining ring. At a
very high speed, the governor valve will be opened as
far as possible. In this condition, it is possible for
governor pressure to meet, but not to exceed, line
pressure. Generally governor pressure ranges from
0-100 psi from idle to maximum speed, and rises pro-
portionally with the increase in output shaft speed.
Governor pressure and throttle pressure are acting
upon the shift valves to determine when a shift will
occur. Governor pressure is a direct indication of road
speed, and throttle pressure is an indication of
engine load. When both parameters have been met
by the throttle and governor pressures, an upshift or
downshift will occur.
CLEANING
Thoroughly clean all the governor parts in a suit-
able cleaning solution but do not use any type of
caustic cleaning agents.
The governor weight components and the governor
valve, must slide freely in their bores when clean and
dry. Minor surface scratches and burrs can be
smoothed with crocus cloth.
INSPECTION
The aluminum governor valve and outer weight
have a hard coating on them. Check condition of this
Fig. 181 Gearshift Cable Adjustment
1 - SHIFT CABLE ADJUSTMENT
2 - SHIFT CABLE
21 - 104 31TH AUTOMATIC TRANSAXLERS
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coating carefully. Do not reuse either part if the coat-
ing is damaged.
Inspect the governor weight spring for distortion.
Replace the spring, if distorted, collapsed, or broken.
Clean the filter in solvent and dry it with compressed
air. Replace the filter, if damaged. Inspect the park
gear for chipped or worn gear teeth or damaged ring
grooves. Replace the gear, if damaged.
Check the teeth on the park gear for wear or dam-
age. Replace the gear if necessary. Inspect the metal
seal rings on the park gear hub. Replace the rings
only if severely worn, or broken.
OIL PUMP
DESCRIPTION
The oil pump is located in the pump housing inside
the bell housing of the transmission case. The oil
pump consists of an inner and outer gear, a housing,
and a cover that also serves as the reaction shaft
support (Fig. 182).
OPERATION
As the torque converter rotates, the converter hub
rotates the inner and outer gears. As the gears
rotate, the clearance between the gear teeth
increases in the crescent area, and creates a suction
at the inlet side of the pump. This suction drawsfluid through the pump inlet from the oil pan. As the
clearance between the gear teeth in the crescent area
decreases, it forces pressurized fluid into the pump
outlet and to the valve body.
STANDARD PROCEDURE - OIL PUMP VOLUME
CHECK
Measuring the oil pump output volume will deter-
mine if sufficient oil flow to the transmission oil
cooler exists, and whether or not an internal trans-
mission failure is present.
Verify that the transmission fluid is at the proper
level. Refer to the Fluid Level Check procedure in
this section. If necessary, fill the transmission to the
proper level with MopartATF +4, type 9602, Auto-
matic Transmission Fluid.
(1) Using hose cutters or a suitable blade, cut the
To coolerline off flush with the cooler inlet fitting
and place a collecting container under the open line.
CAUTION: With the fluid set at the proper level,
fluid collection should not exceed (1) quart or inter-
nal damage to the transmission may occur.
(2) Run the engineat curb idle speed, with the
shift selector in neutral.
(3) If one quart of transmission fluid is collected in
the container in 20 seconds or less, oil pump flow vol-
ume is within acceptable limits. If fluid flow is inter-
Fig. 182 Oil Pump Assembly
1 - REACTION SHAFT SUPPORT
2 - INNER GEAR
3 - PUMP BODY4 - PUMP BUSHING
5 - OUTER GEAR
RS31TH AUTOMATIC TRANSAXLE21 - 105
GOVERNOR (Continued)
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mittent, or it takes more than 20 seconds to collect
one quart of fluid, (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 31TH - DIAGNOSIS
AND TESTING) for further diagnosis.
(4) Re-connect theTo coolerline to the transmis-
sion cooler inlet using a service splice kit. Refer to
instructions included with the kit.
(5) Refill the transmission to proper level. (Refer
to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC
- 31TH/FLUID - STANDARD PROCEDURE)
DISASSEMBLY
(1) Remove reaction shaft support-to-pump body
bolts.
(2) Remove reaction shaft support, and the inner
and outer pump gears (Fig. 183).
CLEANING
Clean pump and support components with solvent
and dry them with compressed air.
INSPECTION
(1) Check condition of the seal rings and thrust
washer on the reaction shaft support. The seal rings
do not need to be replaced unless cracked, broken, or
severely worn.
(2) Visually inspect the pump and support compo-
nents. Replace the pump assembly if the seal ring
grooves or machined surfaces are worn, scored, pit-
ted, or damaged. Replace the pump assembly if the
gears if pitted, worn chipped, or damaged.
(3) Inspect the pump bushing. Then check the
reaction shaft support bushing. Replace the pump
assembly if either bushing is heavily worn, scored or
damaged.
(4) Clearance between outer gear and reaction
shaft housing should be 0.010 to 0.063 mm (0.0004 to
0.0025 in.). Clearance between inner gear and reac-
tion shaft housing should be 0.010 to 0.063 mm
(0.0004 to 0.0025 in.). Both clearances can be mea-
sured at the same time by installing the gears in the
pump body and measure pump component clearances
as follows:
Fig. 183 Oil Pump Assembly
1 - REACTION SHAFT SUPPORT
2 - INNER GEAR
3 - PUMP BODY4 - PUMP BUSHING
5 - OUTER GEAR
21 - 106 31TH AUTOMATIC TRANSAXLERS
OIL PUMP (Continued)
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