
(transmission fluid) this indicates that the Transmis-
sion differential carrier seal should be replaced. If
the fluid leaking is light brown (gear lube) this indi-
cates that the Power Transfer Unit input seal should
be replaced. For replacement of these seals refer to
Power Transfer Unit Service Procedures.
If fluid is leaking from weep hole B (Fig. 5) the
type of fluid leaking will determine which seal is
leaking. If the fluid leaking is red in color (transmis-
sion fluid) this indicates that the input shaft end seal
should be replaced. If the fluid leaking is light brown
(gear lube) this indicates that the half shaft innerseal and P.T.U. input shaft cover seal should be
replaced. For replacement of these seals refer to
Power Transfer Unit Service Procedures.
Before condemning any seal or gasket be sure that
the rear rocker arm cover on the engine is not the
cause of the oil leak. Oil leaking from the rocker arm
cover is easily mistaken for a leaking Power Transfer
Unit.
STANDARD PROCEDURE - FLUID LEVEL
INSPECTION
(1) Raise vehicle on hoist.
(2) Remove PTU inspection plug (Fig. 6).
(3) Fluid level should be within 3/16º from bottom
of inspection hole. Add Moparž Gear and Axle Lubri-
cant 80W-90 as necessary with suitable suction gun
(Fig. 7).
(4) Install inspection plug and torque to 20 N´m
(180 in. lbs.) torque.
(5) Lower vehicle.
STANDARD PROCEDURE - PTU FLUID CHANGE
NOTE: PTU Fluid should be changed upon servic-
ing the unit, or at the unit's regular scheduled inter-
val. (Refer to LUBRICATION & MAINTENANCE/
MAINTENANCE SCHEDULES - DESCRIPTION)
(1) Raise vehicle on hoist.
(2) Remove PTU inspection plug (Fig. 8).
Fig. 3 Seal Location
1 - INPUT SHAFT
2 - OUTPUT SHAFT
3 - REAR COVER
4 - P.T.U. CASE
5 - INPUT SHAFT SEAL
Fig. 4 Seal Location
1 - P.T.U. INPUT SHAFT COVER SEAL
2 - HALF SHAFT INNER SEAL
3 - INSIDE VIEW OF P.T.U. END COVER
Fig. 5 Weep Hole Locations
1 - ENGINE OIL PAN
2 - WEEP HOLE ªAº
3 - TRANSAXLE CASE
4 - P.T.U.
5 - WEEP HOLE ªBº
21 - 4 POWER TRANSFER UNITRS
POWER TRANSFER UNIT (Continued)

INPUT SHAFT COVER SEAL
REMOVAL
The power transfer unit input shaft cover seal is
the larger of the two seals located on the inside of
the end cover. The differential bearing cup must be
removed to service this seal.
(1) Remove P.T.U. end cover bolts (Fig. 30).
(2) Gently tap on end cover ears to separate cover
from case (Fig. 31).
(3) Use special tool No. 6514 and remove the dif-
ferential bearing race located in the end cover (Fig.
32). The race must be removed to gain access to the
seal.
(4) Use special tool No. 7794-A to remove seal (Fig.
33).
Fig. 27 Seal Removal
1 - END COVER
2 - END COVER SEAL
3 - AXLE SHAFT SEAL
Fig. 28 Seal Installation
1 - END COVER
2 - SOCKET
3 - HAMMER
Fig. 29 Bolt Tightening Sequence
RSPOWER TRANSFER UNIT21-13
HALF SHAFT INNER SEAL (Continued)

INSTALLATION
The power transfer unit input shaft cover seal is
the larger of the two seals located on the inside of
the end cover. The differential bearing cup must be
removed to service this seal.
(1) Clean and inspect seal area.
(2) Use special tool No. MD998803 and install seal
(Fig. 34). When installing seal the spring side of the
seal must face toward the special tool.
(3) Reinstall the original bearing race and shim
using special tool No. 6522 (Fig. 35) and (Fig. 36).
Fig. 30 P.T.U. End Cover Bolts
1 - POWER TRANSFER UNIT
2 - FILL PLUG
3 - END COVER
4 - OUTPUT SHAFT
Fig. 31 End Cover Removal
1 - END COVER EARS
2 - HAMMER
3 - POWER TRANSFER UNIT
Fig. 32 Bearing Race Removal
1 - END COVER
2 - SPECIAL TOOL No. 6514
Fig. 33 Seal Removal
1 - END COVER
2 - SPECIAL TOOL 7794±A
3 - SLIDE HAMMER
4 - SOFT JAW VICE
21 - 14 POWER TRANSFER UNITRS
INPUT SHAFT COVER SEAL (Continued)

(5) Place end cover onto P.T.U. case and install
bolts. Tighten bolts to 28 N´m (250 in. lbs.) in the
sequence shown in (Fig. 41). Retighten first bolt after
all others are tight.
CAUTION: When end cover is installed be careful
not to damage the P.T.U. Input Shaft Cover Seal.
(6) Reinstall P.T.U. assembly.
(7) Check and fill fluids as required.
INPUT SHAFT SEAL
REMOVAL
The Power Transfer Unit must be removed from
the vehicle to service this seal. Refer to Power Trans-
fer Unit Removal in this section for procedures.
(1) Remove P.T.U. end cover bolts (Fig. 42).
(2) Gently tap on end cover ears to separate cover
from case (Fig. 43).
(3) Remove ring gear oil trough (Fig. 44).
(4) Remove input shaft and ring gear from case
(Fig. 45).
(5) Use Special Tool No. 7794-A (seal puller) to
remove seal (Fig. 46).
Fig. 41 Bolt Tightening Sequence
Fig. 42 P.T.U. End Cover Bolts
1 - POWER TRANSFER UNIT
2 - FILL PLUG
3 - END COVER
4 - OUTPUT SHAFT
Fig. 43 End Cover Removal
1 - END COVER EARS
2 - HAMMER
3 - POWER TRANSFER UNIT
RSPOWER TRANSFER UNIT21-17
INPUT SHAFT END SEAL (Continued)

INSTALLATION
The Power Transfer Unit must be removed from
the vehicle to service this seal. Refer to Power Trans-
fer Unit Removal in this section for procedures.(1) Clean and inspect seal area.
(2) Lay housing on bench and install new seal with
seal driver C-4657 and handle C-4171 (Fig. 47). The
seal must be installed with the spring side facing
towards the ring gear. Drive the seal in until it bot-
toms against the case shoulder.
(3) Install input shaft.
(4) Install oil trough.
(5) Apply Moparž Gasket Maker or equivalent to
sealing surfaces of end cover and reinstall. Tighten
bolts to 28 N´m (250 in. lbs.)
CAUTION: When end cover is installed be careful
not to damage the P.T.U. Input Shaft Cover Seal.
(6) Reinstall P.T.U. assembly into vehicle.
(7) Check and fill fluids as required.
OUTER HALF SHAFT SEAL
REMOVAL
The outer half shaft seal is located on the outside
of the end cover. The P.T.U. does not have to be
removed to replace this seal.
(1) Lift vehicle on hoist.
(2) Remove right front half shaft from vehicle.
(3) Remove seal with a chisel and hammer (Fig.
48).
Fig. 44 Oil Trough
1 - OIL TROUGH
2 - POWER TRANSFER UNIT
Fig. 45 Input Shaft and Ring Gear Removal
1 - POWER TRANSFER UNIT
2 - RING GEAR
Fig. 46 Seal Removal
1 - POWER TRANSFER UNIT
2 - SPECIAL TOOL
7794±A
21 - 18 POWER TRANSFER UNITRS
INPUT SHAFT SEAL (Continued)

OPERATION
Transmission output is directed to an integral dif-
ferential by a transfer gear system in the following
input-to-output ratios:
FIRST 2.69:1
SECOND 1.55:1
THIRD 1.00:1
REVERSE 2.10:1
DIAGNOSIS AND TESTING - PRELIMINARY
DIAGNOSIS
Automatic transaxle malfunctions are usually
caused by the following general conditions:
²Improper fluid level/condition
²Poor engine performance
²Improper engine or transaxle adjustments
²Transaxle hydraulic malfunctions²Transaxle mechanical malfunctions
Diagnosis of transaxle problems should always
begin with checking the easily accessible variables:
²Fluid level and condition
²Gearshift cable adjustment
²Throttle valve cable adjustment
After verifying or adjusting these variables, road
test the vehicle to determine if the problem has been
corrected or that further diagnosis is necessary. If the
problem still exists, refer to the following diagnosis
charts to aid in determining the source or cause of
failure.
Hydraulic pressure tests should be performed
when a transaxle internal failure is suspected. The
hydraulic flow charts, in the Schematics and Dia-
grams section of this group, outline fluid flow and
hydraulic circuitry. Circuit operation is provided for
all gear ranges. Normal working pressures are also
supplied for each of the gear ranges.
TRANSAXLE DIAGNOSIS CHARTS
CONDITION POSSIBLE CAUSES CORRECTION
HARSH ENGAGEMENT
(FROM NEUTRAL TO
DRIVE OR REVERSE)1. Fluid Level Low 1. Add Fluid
2. Throttle Linkage Misadjusted 2. Adjust linkage - setting may be too
long.
3. Excessive Pinion Backlash 3. Check per Service Manual. Correct as
needed.
4. Hydraulic Pressure Incorrect 4. Check pressure. Remove, overhaul or
adjust valve body as needed.
5. Band Misadjusted. 5. Adjust rear band.
6. Valve Body Check Balls Missing. 6. Inspect valve body for proper check
ball installation.
7. Clutch, band or planetary component
Damaged.7. Remove, disassemble and repair
transmission as necessary.
8. Converter Clutch (if equipped) Faulty. 8. Replace converter and flush cooler and
line before installing new converter.
21 - 24 AUTOMATIC - 31THRS
AUTOMATIC - 31TH (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
NO DRIVE OR
REVERSE (VEHICLE
WILL NOT MOVE)1. Fluid Level Low. 1. Add fluid and check for leaks if drive is
restored.
2. Gearshift Linkage/Cable Loose/
Misadjusted.2. Inspect, adjust and reassemble linkage
as needed. Replace worn/damaged parts.
3. Filter Plugged. 3. Remove and disassemble transmission.
Repair or replace failed components as
needed. Replace filter. If filter and fluid
contained clutch material or metal
particles, an overhaul may be necessary.
Perform lube flow test. Flush oil. Replace
cooler as necessary.
4. Oil Pump Damaged. 4. Perform pressure test to confirm low
pressure. Replace pump body assembly if
necessary.
5. Valve Body Malfunctioned. 5. Check press and inspect valve body.
Replace valve body (as assembly) if any
valve or bore is damaged. Clean and
reassemble correctly if all parts are in
good condition.
6. Transmission Internal Component
Damaged.6. Remove and disassemble transmission.
Repair or replace failed components as
needed. Remove and disassemble
transmission. Repair or replace failed
components as needed.
7. Park Sprag not Releasing - Check Stall
Speed, Worn/Damaged/Stuck.7. Remove, disassemble, repair.
8. Torque Converter Damage. 8. Inspect and replace as required.
SHIFTS DELAYED OR
ERRATIC (ALSO
SHIFTS HARSH AT
TIMES)1. Fluid Level Low/High. 1. Correct fluid level and check for leaks if
low.
2. Fluid Filter Clogged. 2. Replace filter. If filter and fluid
contained clutch material or metal
particles, an overhaul may be necessary.
Perform lube flow test.
3. Throttle Linkage Misadjusted. 3. Adjust linkage as described in service
section.
4. Throttle Linkage Binding. 4. Check cable for binding. Check for
return to closed throttle at transmission.
5. Gearshift Linkage/Cable Misadjusted. 5. Adjust linkage/cable as described in
service section.
6. Governor Valve Sticking. 6. Inspect, clean or repair.
7. Governor Seal Rings Worn/Damaged. 7. Inspect/replace.
8. Clutch or Servo Failure. 8. Remove valve body and air test clutch,
and band servo operation. Disassemble
and repair transmission as needed.
9. Front Band Misadjusted. 9. Adjust band.
10. Pump Suction Passage Leak. 10. Check for excessive foam on dipstick
after normal driving. Check for loose
pump bolts, defective gasket. Replace
pump assembly if needed.
21 - 26 AUTOMATIC - 31THRS
AUTOMATIC - 31TH (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
NO REVERSE (D
RANGES OK)1. Gearshift Linkage/Cable Misadjusted/
Damaged.1. Repair or replace linkage parts as
needed.
2. Rear Band Misadjusted/Worn. 2. Adjust band; replace.
3. Valve Body Malfunction. 3. Remove and service valve body.
Replace valve body if any valves or valve
bores are worn or damaged.
4. Rear Servo Malfunction. 4. Remove and disassemble transmission.
Replace worn/damaged servo parts as
necessary.
5. Direct Clutch in Overdrive Worn 5. Disassemble overdrive. Replace worn
or damaged parts.
6. Front Clutch Burnt. 6. Remove and disassemble transmission.
Replace worn, damaged clutch parts as
required.
HAS FIRST/REVERSE
ONLY (NO 1-2 OR 2-3
UPSHIFT)1. Governor Valve, Shaft, Weights or
Body Damaged/Stuck.1. Remove governor assembly and clean
or repair as necessary.
2. Valve Body Malfunction. 2. Stuck 1-2 shift valve or governor plug.
3. Front Servo/Kickdown Band Damaged/
Burned.3. Repair/replace.
MOVES IN 2ND OR
3RD GEAR, ABRUPTLY
DOWNSHIFTS TO
LOW1. Valve Body Malfunction. 1. Remove, clean and inspect. Look for
stuck 1-2 valve or governor plug.
2. Governor Valve Sticking. 2. Remove, clean and inspect. Replace
faulty parts.
NO LOW GEAR
(MOVES IN 2ND OR
3RD GEAR ONLY)1. Governor Valve Sticking. 1. Remove governor, clean, inspect and
repair as required.
2. Valve Body Malfunction. 2. Remove, clean and inspect. Look for
sticking 1-2 shift valve, 2-3 shift valve,
governor plug or broken springs.
3. Front Servo Piston Cocked in Bore. 3. Inspect servo and repair as required.
4. Front Band Linkage Malfunction 4. Inspect linkage and look for bind in
linkage.
NO KICKDOWN OR
NORMAL DOWNSHIFT1. Throttle Linkage Misadjusted. 1. Adjust linkage.
2. Accelerator Pedal Travel Restricted. 2. Floor mat under pedal, accelerator
cable worn or brackets bent.
3. Governor/Valve Body Hydraulic
Pressures Too High or Too Low Due to
Sticking Governor, Valve Body
Malfunction or Incorrect Hydraulic Control
Pressure Adjustments.3. Perform hydraulic pressure tests to
determine cause and repair as required.
Correct valve body pressure adjustments
as required.
4. Valve Body Malfunction. 4. Perform hydraulic pressure tests to
determine cause and repair as required.
Correct valve body pressure adjustments
as required.
5. Valve Body Malfunction. 5. Sticking 1-2, 2-3 shift valves, governor
plugs, 3-4 solenoid, 3-4 shift valve, 3-4
timing valve.
RSAUTOMATIC - 31TH21-27
AUTOMATIC - 31TH (Continued)