(4) Apply a bead of MopartSilicone Rubber Adhe-
sive Sealant to the adapter plate. Load differential
assembly into position and install adapter plate.
(5) Using Tool L-4435, index adapter plate until
bolt holes align.
(6) Install adapter plate-to-transaxle case bolts
and torque to 28 N´m (250 in. lbs.) torque.
(7) Apply a bead of MopartSilicone Rubber Adhe-
sive Sealant to the differential bearing retainer (Fig.
157).
(8) Install bearing retainer and index using Tool
L-4435 until bolt holes align (Fig. 158).(9) Install and torque bearing retainer bolts to 34
N´m (25 ft. lbs.) torque (Fig. 159).
(10) Install bearing retainer axle seal using Tool
L-4520 (inverted), and driver handle C-4171 (Fig.
160).
Fig. 157 Differential Bearing Retainer (Typical)
1 - DIFFERENTIAL BEARING CUP
2 - DIFFERENTIAL
3 - DIFFERENTIAL BEARING RETAINER
Fig. 158 Index Bearing Retainer using Tool L-4435
1 - GOVERNOR PRESSURE PLUG
2 - DIFFERENTIAL BEARING RETAINER
3 - SPECIAL TOOL L-4435
Fig. 159 Differential Bearing Retainer Bolts
1 - DIFFERENTIAL BEARING RETAINER
2 - DIFFERENTIAL BEARING RETAINER BOLTS (6)
Fig. 160 Install Bearing Retainer Axle Seal
1 - SPECIAL TOOL L-4520
2 - SPECIAL TOOL C-4171
21 - 96 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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(4) Using Tool L-4436A and an inch-pound torque
wrench, check the turning torque of the differential
(Fig. 164).Turning torque should be within 5±18
in. lbs.
(5) If the turning torque is within specifications,
remove tools. Setup is complete.
(6) If turning torque is not within specifications
proceed with the following steps to obtain proper
shim selection:
(a) Remove differential bearing retainer from
the transaxle case.
(b) Remove the bearing cup from the differential
bearing retainer using Tool 6062A.
(c) Remove the existing shim from under the
cup.
(d) Measure the existing shim.
NOTE: If the turning torque was too high when
measured, install a 0.05 mm (0.002 inch) thinner
shim. If the turning torque is was too low, install a
0.05 mm (0.002 inch) thicker shim. Repeat until 5 to
18 inch-pounds turning torque is obtained. Refer to
the ªDifferential Bearing Shim Chart.º Oil Baffle is
not required when making shim selection.
(e) Install the proper shim under the bearing
cup. Make sure the oil baffle is installed properly
in the bearing retainer, below the bearing shim
and cup.
(f) Install the differential bearing cup, shim, and
oil baffle using Tool 5052 and C-4171. Seal the
retainer to the housing with MOPARtSilicone
Rubber Adhesive Sealant and torque bolts to 28
N´m (250 in. lbs.).DIFFERENTIAL BEARING SHIM CHART
SHIM THICKNESS
MM INCH
.980 0.0386
1.02 0.0402
1.06 0.0418
1.10 0.0434
1.14 0.0449
1.18 0.0465
1.22 0.0481
1.26 0.0497
1.30 0.0512
1.34 0.0528
1.38 0.0544
1.42 0.0560
1.46 0.0575
1.50 0.0591
1.54 0.0607
1.58 0.0623
1.62 0.0638
1.66 0.0654
1.70 0.0670
2.02 0.0796
2.06 0.0812
(7) Using Tool L-4436A and an inch-pound torque
wrench, recheck differential turning torque.Turning
torque should be within 5±18 in. lbs.
Fig. 164 Checking Differential Bearings Turning
Torque
1 - SPECIAL TOOL L-4436±A
2 - TORQUE WRENCH
21 - 98 31TH AUTOMATIC TRANSAXLERS
FINAL DRIVE (Continued)
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FLUID
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL AND
CONDITION CHECK
NOTE: The transmission and differential sump have
a common oil sump with a communicating opening
between the two.
FLUID LEVEL CHECK
The torque converter fills in both the P Park and N
Neutral positions. Place the selector lever in P Park
to be sure that the fluid level check is accurate.The
engine should be running at idle speed for at
least one minute, with the vehicle on level
ground. This will assure complete oil level sta-
bilization between differential and transmis-
sion.The fluid should be at normal operating
temperature (approximately 82 C. or 180 F.). The
fluid level is correct if it is in the HOT region (cross-
hatched area) on the fluid level indicator (Fig. 165).
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transaxle has too much fluid, the
gears churn up foam and cause the same conditions
which occur with a low fluid level.
In either case, the air bubbles can cause overheat-
ing, fluid oxidation, and varnishing. This can inter-
fere with normal valve, clutch, and servo operation.
Foaming can also result in fluid escaping from thetransaxle dipstick where it may be mistaken for a
leak.
FLUID CONDITION
Along with fluid level, it is important to check the
condition of the fluid. MopartATF+4 (Automatic
Transmission Fluid-Type 9602) when new is red in
color. The ATF is dyed red so it can be identified from
other fluids used in the vehicle such as engine oil or
antifreeze. The red color is not permanent and is not
an indicator of fluid condition. As the vehicle is
driven, the ATF will begin to look darker in color and
may eventually become brown.This is normal.
ATF+4 also has a unique odor that may change with
age. Consequently,odor and color cannot be used
to indicate the fluid condition, or the need for a
fluid change.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
STANDARD PROCEDURE - FLUID AND FILTER
CHANGE
NOTE: For the recommended maintenance (fluid/fil-
ter change) intervals for this transaxle, (Refer to
LUBRICATION & MAINTENANCE/MAINTENANCE
SCHEDULES - DESCRIPTION)
NOTE: Only fluids of the type labeled MoparTATF+4
(Automatic Transmission Fluid) Type 9602 should
be used. A filter change should be made at the time
of the transmission oil change. The magnet (on the
inside of the oil pan) should also be cleaned with a
clean, dry cloth.
NOTE: If the transaxle is disassembled for any rea-
son, the fluid and filter should be changed.
FLUID/FILTER SERVICE (RECOMMENDED)
(1) Raise vehicle on a hoist. Place a drain con-
tainer with a large opening, under transaxle oil pan.
(2) Loosen pan bolts and tap the pan at one corner
to break it loose allowing fluid to drain, then remove
the oil pan.
(3) Remove oil filter-to-valve body screws (Fig.
166).
(4) Remove oil filter and gasket (Fig. 167).
(5) Install a new filter and gasket (Fig. 167).
(6) Clean the oil pan and magnet. Reinstall pan
using new MopartSilicone Rubber Adhesive Sealant.
Torque oil pan bolts to 19 N´m (165 in. lbs.).
(7) Pour four quarts of MopartATF+4 (Automatic
Transmission Fluid-Type 9602) through the dipstick
opening.
Fig. 165 Fluid Level Indicator Markings
1 - TRANSAXLE DIPSTICK
RS31TH AUTOMATIC TRANSAXLE21-99
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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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(5) Reinstall gears to pump body and measure
outer gear-to-pocket clearance with a feeler gauge
(Fig. 184).Outer gear-to-pocket clearance should
be within 0.045-0.141 mm (0.0018-0.0056 in.).
(6) Measure both inner and outer gear side clear-
ance with PlastigageŸ. If PlastigageŸ is not avail-
able, measure across the pump body with a straight
edge and feeler gauge.
(a) Position an appropriate piece of PlastigageŸ
across both gears.
(b) Align the plastigage to a flat area on the
reaction shaft housing.
(c) Install the reaction shaft support to the
pump housing and torque to 28 N´m (250 in. lbs.).
(d) Separate the reaction shaft housing from the
pump housing and measure the PlastigageŸ fol-
lowing the instructions supplied with it.Inner
and outer gear side clearance should be
within 0.020-0.046 mm (0.0008-0.0018 in.).
ASSEMBLY
(1) Install inner and outer gears to pump body
(Fig. 183). Lubricate gears with MopartATF+4
(Automatic Transmission Fluid-Type 9602).
(2) Install reaction shaft support to pump body
and align holes.
(3) Install and torque reaction shaft support-to-
pump body bolts to 28 N´m (250 in. lbs.).
PARK/NEUTRAL POSITION
SWITCH
DIAGNOSIS AND TESTING - PARK/NEUTRAL
POSITION SWITCH
The park/neutral starting switch is the center ter-
minal of the 3 terminal switch. It provides ground for
the starter solenoid circuit through the selector lever
in only Park (P) and Neutral (N) positions.
(1) To test switch, remove wiring connector from
switch and test for continuity between center pin of
switch and transaxle case. Continuity should exist
only when transaxle is in Park or Neutral.
(2) Check gearshift cable adjustment before replac-
ing a switch which tests bad.
REMOVAL
(1) Unscrew switch from transaxle case allowing
fluid to drain into a container. Move selector lever to
Park, then to Neutral position, and inspect to see the
switch operating lever fingers are centered in switch
opening.
INSTALLATION
(1) Screw the switch with a new seal into trans-
axle case and tighten to 33 N´m (24 ft. lbs.). Retest
switch with the test lamp.
(2) Add fluid to transaxle to bring up to proper
level.
(3) The back-up lamp switch circuit is through the
two outside terminals of the 3 terminal switch.
(4) To test switch, remove wiring connector from
switch and test for continuity between the two out-
side pins.
(5) Continuity should exist only with transaxle in
Reverse position.
(6) No continuity should exist from either pin to
the case.Fig. 184 Measuring Pump Outer Gear-to-Pocket
Clearance
1 - FEELER GAUGE
2 - OUTER GEAR
RS31TH AUTOMATIC TRANSAXLE21 - 107
OIL PUMP (Continued)
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(5) Install instrument panel lower silencer (Fig.
221).
(6) Connect battery negative cable.
(7) Verify proper shift interlock system operation.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC - 31TH/SHIFT INTERLOCK SOLENOID -
OPERATION)
SOLENOID - TCC
DESCRIPTION
The torque converter clutch (TCC) solenoid is fas-
tened to the transaxle valve body, and its connector
protrudes through the transaxle case (Fig. 222).
OPERATION
The torque converter clutch solenoid is responsible
for controlling application of the torque converter
clutch. It is controlled by the Powertrain Control
Module (PCM), which determines when conditions
are acceptable for torque converter lock-up.
REMOVAL
(1) Remove valve body from transaxle. (Refer to 21
- TRANSMISSION/TRANSAXLE/AUTOMATIC -
31TH/VALVE BODY - REMOVAL)
(2) Remove three (3) torque converter clutch sole-
noid-to-valve body screws (Fig. 223).
(3) Remove torque converter clutch solenoid (Fig.
223). Note orientation of plug and spring.
Fig. 221 Instrument Panel Lower Silencer
1 - INSTRUMENT PANEL LOWER SILENCER
Fig. 222 Torque Converter Clutch Solenoid
1 - TCC SOLENOID WIRING CONNECTOR
RS31TH AUTOMATIC TRANSAXLE21 - 119
SHIFT INTERLOCK SOLENOID (Continued)
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INSTALLATION
(1) Install plug and spring as shown in (Fig. 223).
(2) Install torque converter clutch solenoid to valve
body (Fig. 223) and torque screws to 5 N´m (45 in.
lbs.).
(3) Install valve body to transaxle. (Refer to 21 -
TRANSMISSION/TRANSAXLE/AUTOMATIC -
31TH/VALVE BODY - INSTALLATION)
THROTTLE VALVE CABLE
REMOVAL
(1) Disconnect battery negative cable.
(2) Disconnect cable core from throttle lever pin
(Fig. 224).
(3) Disconnect cable retainer from throttle body
bracket (Fig. 224).
Fig. 223 Torque Converter Clutch Solenoid and Regulator/Control Valves
1 - CONVERTER PRESSURE CONTROL VALVE 3 - SCREW (3) 5 - REGULATOR VALVE THROTTLE PRESSURE
PLUG
2 - END COVER 4 - REGULATOR VALVE THROTTLE PRESSURE
PLUG SPRING 6 - SWITCH VALVE
Fig. 224 Throttle Valve Cable at Throttle Body
1 - THROTTLE VALVE CABLE CLIP
2 - THROTTLE BODY LEVER
3 - CABLE RETAINER
21 - 120 31TH AUTOMATIC TRANSAXLERS
SOLENOID - TCC (Continued)
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