
SPECIAL TOOLS
31TH AUTOMATIC TRANSAXLE
Adapter Blocks C-293±45
Adapter Blocks C-293±52
Puller Press C-293±PA
Pressure Gauge (High) C-3293SP
Dial Indicator C-3339
Spring Compressor C-3575-A
Band Adjusting Adapter C-3705
Oil Pump Puller C-3752
Throttle Setting Gauge C-3763
Seal Puller C-3981B
21 - 74 AUTOMATIC - 31THRS
AUTOMATIC - 31TH (Continued)

BANDS
KICKDOWN (FRONT) BAND
DESCRIPTION
The kickdown, or ªfrontº, band (Fig. 108) holds the
common sun gear of the planetary gear sets. The
front (kickdown) band is made of steel, and faced on
its inner circumference with a friction-type lining.
One end of the band is anchored to the transmission
case, and the other is acted on with a pushing force
by a servo piston. The front band is a single-wrap
design (the band does not completely encompass/
wrap the drum that it holds).
OPERATION
The kickdown band holds the common sun gear of
the planetary gear sets by applying and holding the
front clutch retainer, which is splined to the sun gear
driving shell, and in turn splined directly to the sun
gear. The application of the band by the servo is typ-
ically done by an apply lever and link bar.
LOW/REVERSE (REAR) BAND
DESCRIPTION
The low/reverse band, or ªrearº, band (Fig. 109) is
similar in appearance and operation to the front
band. The rear band is also a single-wrap design (
the band does not completely encompass/wrap the
drum that it holds).
OPERATION
The rear band holds the rear planet carrier sta-
tionary by being mounted around and applied to the
low/reverse drum.
ADJUSTMENT - FRONT BAND
The front (kickdown) band adjusting screw is
located on the left side of the transmission case
above the manual valve and throttle valve levers.
(1) Disconnect battery negative cable.
(2) Remove air cleaner assembly.
(3) Loosen band adjusting screw locknut (Fig. 110).
Then back locknut off 3-5 turns. Be sure adjusting
screw turns freely in case. Apply lubricant to screw
threads if necessary.
(4) Tighten band adjusting screw to 8 N´m (72 in.
lbs.).
Fig. 108 Front BandÐTypical
1 - FRONT BAND
2 - TRANSMISSION HOUSING
Fig. 109 Rear Band
1 - PLANETARY GEARTRAIN
2 - REAR BAND
3 - LEVER
4 - SERVO
5 - ADJUSTER
Fig. 110 Front (Kickdown) Band Adjustment
Location
1 - KICKDOWN BAND ADJUSTING SCREW
RSAUTOMATIC - 31TH21-79

(5) Back off front band adjusting screw 2ò turns.
(6) Hold adjuster screw in position and tighten
locknut to 47 N´m (35 ft. lbs.) torque.
(7) Install air cleaner assembly.
(8) Connect battery negative cable.
ADJUSTMENTS - REAR BAND
The transmission oil pan must be removed for
access to the rear (low/reverse) band adjusting screw.
(1) Raise vehicle.
(2) Remove transaxle oil pan and drain fluid (Fig.
111) (Fig. 112).(3) Loosen band adjusting screw locknut 5-6 turns.
Be sure adjusting screw turns freely in lever.
(4) Tighten adjusting screw to 5 N´m (41 in. lbs.)
(Fig. 113).
(5) Back off adjusting screw 3 turns.
(6) Hold adjusting screw in place and tighten lock-
nut to 14 N´m (125 ft. lbs.) torque.
(7) Install a bead of Moparž Silicone Rubber Adhe-
sive Sealant to the oil pan and install to case imme-
diately.
(8) Install oil pan-to-case bolts and torque to 19
N´m (165 in. lbs.).
(9) Lower vehicle and refill transmission with
Moparž ATF Plus 4, Type 9602, fluid.
CLUTCH - FRONT
DESCRIPTION
The front clutch assembly (Fig. 119) is composed of
the front clutch retainer, pressure plate, clutch
plates, driving discs, piston, piston return spring,
return spring retainer, and snap-rings. The front
clutch is the forward-most component in the trans-
mission geartrain and is directly behind the oil
pump. It is considered a driving component.
NOTE: The number of discs and plates may vary
with each engine and vehicle combination.
Fig. 111 Transaxle Oil Pan Bolts
1 - TRANSAXLE OIL PAN
2 - OIL PAN BOLTS
Fig. 112 Transaxle Oil Pan
1 - TRANSAXLE OIL PAN
2 - OIL FILTER
Fig. 113 Adjust Low/Reverse Band
1 - LOW-REVERSE BAND LEVER
2 - ADJUSTING SCREW
3 - STRUT
4 - LOW-REVERSE BAND
5 - LOCK NUT
6 - LEVER (SHORT)
21 - 80 AUTOMATIC - 31THRS
BANDS (Continued)

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
Fig. 180 Gearshift Cable at Transaxle
1 - MANUAL VALVE LEVER
2 - GEAR SHIFT CABLE
3 - UPPER MOUNT BRACKET
Fig. 181 Gearshift Cable Adjustment
1 - SHIFT CABLE ADJUSTMENT
2 - SHIFT CABLE
RSAUTOMATIC - 31TH21 - 103
GEAR SHIFT CABLE (Continued)

(3) Remove retainer, spring and servo (Fig. 206).
CLEANING
Remove and discard the servo piston seal ring (Fig.
207). Then clean the servo components with solvent
and dry with compressed air. Replace either spring if
collapsed, distorted or broken. Replace the plug and
piston if cracked, bent, or worn. Discard the servo
snap-rings and use new ones at assembly.
ASSEMBLY
(1) Install low/reverse servo assembly (Fig. 208).
(2) Install low/reverse servo snap ring (Fig. 205).
SHIFT INTERLOCK SOLENOID
DESCRIPTION
The Brake/Transmission Shift Interlock system
consists of an electro-magnetic solenoid mounted to
the steering column (Fig. 209). The solenoid's plunger
consists of an integrated hook, which operates the
shift lever pawl (part of shift lever assembly), and a
plunger return spring (Fig. 210). The solenoid also
has an integrated bracket, which facilitates fastening
to the steering column.
Fig. 206 Remove Retainer, Spring and Servo
1 - SERVO PISTON
2 - SPRING AND RETAINER
Fig. 207 Rear Servo Components
1 - SNAP-RING
2 - PISTON SEAL
3 - PISTON PLUG
4 - SPRING RETAINER
5 - SNAP-RING
6 - PISTON SPRING
7 - CUSHION SPRING
8 - PISTON
Fig. 208 Low/Reverse Servo Assembly
1 - SERVO PISTON
2 - SPRING
Fig. 209 Brake/Transmission Shift Interlock (BTSI)
Solenoid Location
1 - BTSI SOLENOID
RSAUTOMATIC - 31TH21 - 113
SERVO - LOW/REVERSE (Continued)

OPERATION
The Brake/Transmission Shift Interlock (BTSI)
Solenoid prevents the transmission shift lever from
being moved out of PARK (P) unless the brake pedal
is applied. The BTSI solenoid is hardwired to and
controlled by the Intelligent Power Module (IPM).
Battery voltage is applied to one side of the solenoid
with the ignition key is in either the ON/RUN or
START positions (Fig. 211). The ground side of the
solenoid is controlled by a driver within the IPM. It
relies on voltage supplied from the stop lamp switch
to the stop lamp sense circuit within the IPM to tell
when the brake pedal is depressed. When the brake
pedal is depressed, the ground circuit opens, de-ener-
gizing the solenoid. When the brake pedal is
released, the ground circuit is closed, energizing the
solenoid.
When the ignition key is in either the ON/RUN or
START positions, the BTSI solenoid is energized, and
the solenoid plunger hook pulls the shift lever pawl
into position, prohibiting the shift lever from moving
out of PARK (P) (Fig. 212). When the brake pedal is
depressed, the ground circuit opens, de-energizing
the solenoid. This moves the gearshift lever pawl out
of the way (Fig. 213), allowing the shift lever to be
moved into any gear position.
Fig. 210 Solenoid Plunger and Return Spring
1 - PLUNGER
2 - RETURN SPRING
3 - BTSI SOLENOID
Fig. 211 Ignition Key/Switch Positions
1 - ACC
2 - LOCK
3 - OFF
4 - ON/RUN
5-START
Fig. 212 Pawl Engaged to Shift Lever
1 - GEAR SHIFT LEVER
2 - GEAR SHIFT LEVER PAWL
21 - 114 AUTOMATIC - 31THRS
SHIFT INTERLOCK SOLENOID (Continued)

A conventional mechanical interlock system is also
used. This system manually prohibits shifter move-
ment when the ignition switch is in the LOCK or
ACC positions. Solenoid operation is not required in
these key positions. When the ignition key is in the
OFF position, the gearshift lever is unrestricted, and
able to move into any gear position (during towing,
dead battery, etc.).
For intended BTSI system operation, refer to the
following chart:
ACTION EXPECTED RESPONSE
1. Turn key to the9OFF9
position.1. Shifter CAN be shifted
out of park.
2. Turn key to the
9ON/RUN9position.2. Shifter CANNOT be
shifted out of park.
3. Turn key to the
9ON/RUN9position and
depress the brake pedal.3. Shifter CAN be shifted
out of park.
4. Leave shifter in any
gear and try to return key
to the9LOCK9or9ACC9
position.4. Key cannot be
returned to the9LOCK9or
9ACC9position.
5. Return shifter to
9PARK9and try to remove
the key.5. Key can be removed
(after returning to9LOCK9
position).
6. With the key removed,
try to shift out of9PARK9.6. Shifter cannot be
shifted out of9PARK9.
NOTE: Any failure to meet these expected
responses requires system adjustment or repair.
DIAGNOSIS AND TESTING - BRAKE/
TRANSMISSION SHIFT INTERLOCK SOLENOID
For intended BTSI system operation, refer to the
following chart:
ACTION EXPECTED RESPONSE
1. Turn key to the9OFF9
position.1. Shifter CAN be shifted
out of park.
2. Turn key to the
9ON/RUN9position.2. Shifter CANNOT be
shifted out of park.
3. Turn key to the
9ON/RUN9position and
depress the brake pedal.3. Shifter CAN be shifted
out of park.
4. Leave shifter in any
gear and try to return key
to the9LOCK9or9ACC9
position.4. Key cannot be
returned to the9LOCK9or
9ACC9position.
5. Return shifter to
9PARK9and try to remove
the key.5. Key can be removed
(after returning to9LOCK9
position).
6. With the key removed,
try to shift out of9PARK9.6. Shifter cannot be
shifted out of9PARK9.
NOTE: Any failure to meet these expected
responses requires system repair. Refer to the
appropriate Diagnostic Information.
REMOVAL
(1) Disconnect battery negative cable.
(2) Remove instrument panel lower shroud (Fig.
214).
Fig. 213 Pawl Disengaged From Shift Lever
1 - GEAR SHIFT LEVER
2 - GEAR SHIFT LEVER PAWL
Fig. 214 Instrument Panel Lower Silencer
1 - INSTRUMENT PANEL LOWER SILENCER
RSAUTOMATIC - 31TH21 - 115
SHIFT INTERLOCK SOLENOID (Continued)

(3) Remove knee bolster (Fig. 215).
(4) Remove steering column lower shroud.
(5) Disconnect brake/transmission shift interlock
(BTSI) solenoid connector (Fig. 216).
(6) Remove two (2) solenoid-to-column screws (Fig.
217).
(7) Remove solenoid.
INSTALLATION
(1) Place interlock solenoid into position ensuring
hook on end of solenoid plunger engages gearshift
lever pawl pin. Install and tighten screws (Fig. 218).
Fig. 215 Knee Bolster
1 - KNEE BOLSTER
Fig. 216 BTSI Solenoid Connector
1 - BTSI SOLENOID
2 - SOLENOID CONNECTOR
Fig. 217 Solenoid Retaining Screw
1 - SOLENOID RETAINING SCREW (2)
Fig. 218 Solenoid Retaining Screw
1 - SOLENOID RETAINING SCREW (2)
21 - 116 AUTOMATIC - 31THRS
SHIFT INTERLOCK SOLENOID (Continued)