
OPERATION
The Transfer Unit provides the power to the rear
wheels through a hypoid ring gear and pinion set.
DIAGNOSIS AND TESTING - SEAL
IDENTIFICATION
For accurate seal diagnosis, repair seal name and
location is critical. Refer to (Fig. 1), (Fig. 2), (Fig. 3)
and (Fig. 4) for correct seal name and location.
DIAGNOSIS AND TESTING - FLUID LEAK
DIAGNOSIS
When diagnosing fluid leaks on the Power Transfer
Unit two weep holes are provided to diagnose certain
seal leaks. These holes are located on the bottom side
of the assembly (Fig. 5).
If fluid leak is detected from either weep hole, seal
replacement is necessary.Do not attempt to repair
the leak by sealing weep holes,they must be kept
clear of sealants for proper seal operation.
If fluid is leaking from weep hole A (Fig. 5) the
type of fluid leaking will determine which seal needs
to be replaced. If the fluid leaking is red in color
1 - PLUG 18 - CASE-PTU 35 - SHIM
2 - WASHER FLAT 19 - PINION-PTU 36 - TAPERED ROLLER BEARING
3 - SEAL RING 20 - O-RING 37 - SHAFT ASSY. FRONT L.H.
4 - SNAP RING 21 - SHIM 38 - SEAL RING
5 - BALL BEARING 22 - TAPERED ROLLER BEARING 39 - OIL WIPER
6 - SEAL RING 23 - COVER-PTU CASE REAR 40 - RETAINER DIFFERENTIAL BEARING
7 - COVER-PTU
CASE END24 - FLANGE TUBE-PTU-OUTPUT ASSY. 41 - SHAFT DIFFERENTIAL PINION
8 - TAPERED ROLLER BEARING 25 - LOCK NUT-HEX FLANGE 42 - PIN
9 - SEAL RING 26 - O- RING 43 - CASE DIFFERENTIAL
10 - SEAL RING 27 - RETAINER PLATE 44 - TAPERED ROLLER BEARING CONE
11 - HEX HEAD SCREW 28 - O-RING 45 - SEAL RING
12 - SHAFT-PTU INPUT 29 - BRACKET 46 - SEAL RING
13 - GEAR-PTU RING 30 - THRUST WASHER 47 - PLUG
14 - TROUGH-PTU (RT.) 31 - SIDE GEAR-DIFFERENTIAL 48 - O-RING
15 - TROUGH-PTU (LT.) 32 - FINAL DRIVE GEAR 49 - SHIM
16 - TAPERED ROLLER BEARING 33 - PINION DIFFERENTIAL 50 - MAGNET
17 - HEX HEAD SCREW 34 - WASHER DIFFERENTIAL PINION 51 - DOWEL
52 - SHAFT ASSY. FRONT R.H.
53 - HEX HEAD SCREW
Fig. 1 Seal
1 - INPUT SHAFT
2 - P.T.U. CASE
3 - MAGNET
4 - INPUT SHAFT END SEAL
5 - OUTPUT SHAFT
6 - RING GEAR
7 - REAR COVER
Fig. 2 Seal Location
1 - REAR COVER
2 - END COVER
3 - OUTER HALFSHAFT SEAL
4 - P.T.U. CASE
5 - P.T.U. OUTPUT SEAL
RSPOWER TRANSFER UNIT21-3
POWER TRANSFER UNIT (Continued)

INPUT SHAFT END SEAL
REMOVAL
The input shaft end seal is located on the end of
the input shaft.
(1) Remove power transfer unit from the vehicle.
(2) Remove end cover bolts (Fig. 38).
(3) Tap on end cover ears to separate end cover
from case (Fig. 39).
(4) Pry out seal with a pry bar (Fig. 40).
INSTALLATION
The input shaft end seal is located on the end of
the input shaft.
(1) Clean and inspect seal area.
(2) Remove input shaft from housing and stand on
soft block of wood. Install input shaft end seal with
seal installer 5065 and handle C-4171.
(3) Lubricate seal lip after installing seal into
input shaft.
(4) Clean sealing surfaces of the end cover and
P.T.U. case. Apply a bead of Moparž Gasket Maker,
Loctite Gasket Eliminator No. 518 or equivalent.
Fig. 38 End Cover Bolts
1 - POWER TRANSFER UNIT
2 - FILL PLUG
3 - END COVER
4 - OUTPUT SHAFT
Fig. 39 Side Cover Removal
1 - END COVER EARS
2 - HAMMER
3 - POWER TRANSFER UNIT
Fig. 40 Seal Removal
1 - POWER TRANSFER UNIT
2 - PRYBAR
3 - SEAL
21 - 16 POWER TRANSFER UNITRS

AUTOMATIC - 31TH
TABLE OF CONTENTS
page page
AUTOMATIC - 31TH
DESCRIPTION...........................22
OPERATION.............................24
DIAGNOSIS AND TESTING.................24
PRELIMINARY DIAGNOSIS...............24
ROAD TEST...........................31
HYDRAULIC PRESSURE TESTS...........32
TORQUE CONVERTER HOUSING FLUID
LEAKAGE.............................34
CLUTCH AND SERVO AIR PRESSURE
TESTS...............................35
STANDARD PROCEDURE..................36
ALUMINUM THREAD REPAIR.............36
REMOVAL..............................36
DISASSEMBLY...........................39
ASSEMBLY.............................50
INSTALLATION...........................59
SCHEMATICS AND DIAGRAMS..............63
SPECIFICATIONS........................71
SPECIAL TOOLS.........................74
ACCUMULATOR
DESCRIPTION...........................78
OPERATION.............................78
BANDS
DESCRIPTION...........................79
OPERATION.............................79
ADJUSTMENTS..........................79
CLUTCH - FRONT
DESCRIPTION...........................80
OPERATION.............................81
DISASSEMBLY...........................81
ASSEMBLY.............................84
CLUTCH - REAR
DESCRIPTION...........................85
OPERATION.............................85
DISASSEMBLY...........................86
ASSEMBLY.............................89
FINAL DRIVE
DISASSEMBLY...........................90
ASSEMBLY.............................94
ADJUSTMENTS..........................96
FLUID
STANDARD PROCEDURE..................98
FLUID LEVEL AND CONDITION CHECK......98
FLUID AND FILTER CHANGE..............98
GEAR SHIFT CABLE
REMOVAL.............................100
INSTALLATION..........................101
ADJUSTMENTS.........................103GOVERNOR
DESCRIPTION..........................103
OPERATION............................103
CLEANING.............................104
INSPECTION...........................104
OIL PUMP
DESCRIPTION..........................104
OPERATION............................104
STANDARD PROCEDURE.................105
OIL PUMP VOLUME CHECK..............105
DISASSEMBLY..........................105
CLEANING.............................105
INSPECTION...........................105
ASSEMBLY............................105
PARK/NEUTRAL POSITION SWITCH
DIAGNOSIS AND TESTING................106
PARK/NEUTRAL POSITION SWITCH.......106
REMOVAL.............................106
INSTALLATION..........................107
PLANETARY GEARTRAIN
DISASSEMBLY..........................107
ASSEMBLY............................107
SEAL - OIL PUMP
REMOVAL.............................109
INSTALLATION..........................109
SERVO - KICKDOWN
DESCRIPTION..........................109
OPERATION............................109
DISASSEMBLY..........................110
CLEANING.............................111
INSPECTION...........................111
ASSEMBLY.............................112
SERVO - LOW/REVERSE
DESCRIPTION..........................112
OPERATION............................112
DISASSEMBLY..........................112
CLEANING.............................113
ASSEMBLY.............................113
SHIFT INTERLOCK SOLENOID
DESCRIPTION..........................113
OPERATION............................114
DIAGNOSIS AND TESTING................115
BRAKE/TRANSMISSION SHIFT INTERLOCK
SOLENOID...........................115
REMOVAL.............................115
INSTALLATION..........................116
SOLENOID - TCC
DESCRIPTION..........................117
OPERATION............................117
RSAUTOMATIC - 31TH21-21

CONDITION POSSIBLE CAUSES CORRECTION
SLIPS IN FORWARD
DRIVE RANGES1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Fluid Foaming. 2. Check for high oil level, bad pump
gasket or seals, dirt between pump halves
and loose pump bolts. Replace pump if
necessary.
3. Throttle Linkage Misadjusted. 3. Adjust linkage.
4. Gearshift Linkage Misadjusted. 4. Adjust linkage.
5. Rear Clutch Worn. 5. Inspect and replace as needed.
6. Low Hydraulic Pressure Due to Worn
Pump, Incorrect Control Pressure
Adjustments, Valve Body Warpage or
Malfunction, Sticking Governor, Leaking
Seal Rings, Clutch Seals Leaking, Servo
Leaks, Clogged Filter or Cooler Lines6. Perform hydraulic and air pressure
tests to determine cause.
7. Rear Clutch Malfunction, Leaking Seals
or Worn Plates.7. Air pressure check clutch-servo
operation and repair as required.
8. Overrunning Clutch Worn, Not Holding
(Slips in 1 Only).8. Replace Clutch.
SLIPS IN LOW GEAR
9D9ONLY, BUT NOT IN
1 POSITIONOverrunning Clutch Faulty. Replace overrunning clutch.
GROWLING, GRATING
OR SCRAPING
NOISES1. Drive Plate Broken. 1. Replace.
2. Torque Converter Bolts Hitting Dust
Shield.2. Dust shield bent. Replace or repair.
3. Planetary Gear Set Broken/Seized. 3. Check for debris in oil pan and repair
as required.
4. Overrunning Clutch Worn/Broken. 4. Inspect and check for debris in oil pan.
Repair as required.
5. Oil Pump Components Scored/Binding. 5. Remove, inspect and repair as
required.
6. Output Shaft Bearing or Bushing
Damaged.6. Remove, inspect and repair as
required.
7. Clutch Operation Faulty. 7. Perform air pressure check and repair
as required.
8. Front and Rear Bands Misadjusted. 8. Adjust bands.
DRAGS OR LOCKS UP 1. Fluid Level Low. 1. Check and adjust level.
2. Clutch Dragging/Failed 2. Air pressure check clutch operation and
repair as required.
3. Front or Rear Band Misadjusted. 3. Adjust bands.
4. Case Leaks Internally. 4. Check for leakage between passages
in case.
5. Servo Band or Linkage Malfunction. 5. Air pressure check servo operation and
repair as required.
6. Overrunning Clutch Worn. 6. Remove and inspect clutch. Repair as
required.
7. Planetary Gears Broken. 7. Remove, inspect and repair as required
(look for debris in oil pan).
RSAUTOMATIC - 31TH21-29
AUTOMATIC - 31TH (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
WHINE/NOISE
RELATED TO ENGINE
SPEED1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Shift Cable Incorrect Routing. 2. Check shift cable for correct routing.
Should not touch engine or bell housing.
TORQUE CONVERTER
LOCKS UP IN
SECOND AND/OR
THIRD GEARLockup Solenoid, Relay or Wiring
Shorted/Open.Test solenoid, relay and wiring for
continuity, shorts or grounds. Replace
solenoid and relay if faulty. Repair wiring
and connectors as necessary.
HARSH 1-2 OR 2-3
SHIFTSLockup Solenoid Malfunction. Remove valve body and replace solenoid
assembly.
NO START IN PARK
OR NEUTRAL1. Gearshift Linkage/Cable Misadjusted. 1. Adjust linkage/cable.
2. Neutral Switch Wire Open/Cut. 2. Check continuity with test lamp. Repair
as required.
3. Neutral Switch Faulty. 3. Refer to service section for test and
replacement procedure.
4. Neutral Switch Connect Faulty. 4. Connectors spread open. Repair.
5. Valve Body Manual Lever Assembly
Bent/Worn/Broken.5. Inspect lever assembly and replace if
damaged.
NO REVERSE (OR
SLIPS IN REVERSE)1. Direct Clutch Pack (front clutch) Worn. 1. Disassemble unit and rebuild clutch
pack.
2. Rear Band Misadjusted. 2. Adjust band.
3. Front Clutch Malfunctioned/Burnt. 3. Air pressure test clutch operation.
Remove and rebuild if necessary.
OIL LEAKS (ITEMS
LISTED REPRESENT
POSSIBLE LEAK
POINTS AND SHOULD
ALL BE CHECKED.1. Fluid Lines and Fittings Loose/Leaks/
Damaged.1. Tighten fittings. If leaks persist, replace
fittings and lines if necessary.
2. Filler Tube (where tube enters case)
Leaks/Damaged.2. Replace tube seal. Inspect tube for
cracks in tube.
3. Pressure Port Plug Loose Loose/
Damaged.3. Tighten to correct torque. Replace plug
or reseal if leak persists.
4. Pan Gasket Leaks. 4. Tighten pan screws to 150 inch
pounds. If leaks persist, replace gasket.
Do no over tighten screws.
5. Valve Body Manual Lever Shaft Seal
Leaks/Worn.5. Replace shaft seal.
6. Rear Bearing Access Plate Leaks. 6. Replace gasket. Tighten screws.
7. Gasket Damaged or Bolts are Loose. 7. Replace bolts or gasket or tighten both.
8. Adapter/Extension Gasket Damaged
Leaks/Damaged.8. Replace gasket.
9. Neutral Switch Leaks/Damaged. 9. Replace switch and gasket.
10. Converter Housing Area Leaks. 10. Check for leaks at seal caused by
worn seal or burr on converter hub
(cutting seal), worn bushing, missing oil
return, oil in front pump housing or hole
plugged. Check for leaks past O-ring seal
on pump or past pump-to-case bolts;
pump housing porous, oil coming out vent
due to overfill or leak past front band shaft
access plug.
21 - 30 AUTOMATIC - 31THRS
AUTOMATIC - 31TH (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
11. Pump Seal Leaks/Worn/Damaged. 11. Replace seal.
12. Torque Converter Weld Leak/Cracked
Hub.12. Replace converter.
13. Case Porosity Leaks. 13. Replace case.
DIAGNOSIS AND TESTING - ROAD TEST
Prior to performing a road test, check the fluid
level and throttle valve cable adjustments.
During the road test, the transaxle should be oper-
ated in each position to check for slipping and any
variation in shifting.
If vehicle operates at high speeds, but has poor
acceleration, the converter's overrunning clutch may
be slipping. If acceleration is normal, but high throt-
tle opening is needed for high speeds, the stator
clutch may have seized.Observe closely for slipping or engine speed flare-
up. Slipping or flare-up in any gear usually indicates
clutch, band, or overrunning clutch problems. If the
condition is far advanced, an overhaul will probably
be necessary to restore normal operation.
In most cases, the clutch or band that is slipping
can be determined by noting the transaxle operation
in all selector positions and then comparing which
internal units are applied in those positions. The Ele-
ments±in±Use Chart provides a basis for road test
analysis.
CLUTCHES BANDS
LEVER START PARK
FRONT REAR LOCKUPOVER-
RUNNING(KICKDOWN) LOW/REV
POSITION SAFETY SPRAG FRONT REAR
PÐ
PARKXX
RÐ
REVERSEXX
NÐ
NEUTRALX
DÐ
DRIVE
First X X
Second X X
Third X X X
2Ð
SECOND
First X X
Second X X
1 Ð Low X X
The rear clutch is applied in both the D first gear
and 1 first gear positions. Also, the overrunning
clutch is applied in D first gear and the low/reverse
band is applied in 1 first gear position. If the trans-
axle slips in D range first gear, but does not slip in 1
first gear, the overrunning clutch is slipping. Simi-
larly, if the transaxle slips in any two forward gears,
the rear clutch is slipping.Using the same procedure, the rear clutch and
front clutch are applied in D third gear. If the trans-
axle slips in third gear, either the front clutch or the
rear clutch is slipping. By selecting another gear that
does not use one of those units, the unit that is slip-
ping can be determined. If the transaxle also slips in
reverse, the front clutch is slipping. If the transaxle
does not slip in reverse, the rear clutch is slipping.
RSAUTOMATIC - 31TH21-31
AUTOMATIC - 31TH (Continued)

TEST ONE (SELECTOR IN 1)
(1) Attach gauges to line and low-reverse ports.
(2) Operate engine at 1000 rpm for test.
(3) Move selector lever on transaxle all the way
rearward (1 position).
(4) Read pressures on both gauges as throttle lever
on transaxle is moved from full clockwise position to
full counterclockwise position.
(5) Line pressure should read 52 to 58 psi with
throttle lever clockwise. Pressure should gradually
increase to 80 to 88 psi.as lever is moved counter-
clockwise.
(6) Low/reverse pressure should read the same as
line pressure, within 3 psi.
(7) This tests pump output, pressure regulation,
and condition of rear clutch and rear servo hydraulic
circuits.
TEST TWO (SELECTOR IN 2)
(1) Attach one gauge to line pressure port, and tee
another gauge into lower cooler line fitting. This will
allow lubrication pressure readings to be taken.
(2) Operate engine at 1000 rpm for test.
(3) Move selector lever on transaxle one detent for-
ward from full rearward position. This is selector 2
position.
(4) Read pressures on both gauges as throttle lever
on transaxle is moved from full clockwise position to
full counterclockwise position.
(5) Line pressure should read 52 to 58 psi with
throttle lever clockwise. Pressure should gradually
increase to 80 to 88 psi. as lever is moved counter-
clockwise.
(6) Lubrication pressure should be 10 to 25 psi
with lever clockwise and 10 to 35 psi with lever at
full counterclockwise.(7) This tests pump output, pressure regulation,
and condition of rear clutch and lubrication hydraulic
circuits.
TEST THREE (SELECTOR IN D)
(1) Attach gauges to line and kickdown release
ports.
(2) Operate engine at 1600 rpm for test.
(3) Move selector lever on transaxle two detents
forward from full rearward position. This is selector
D position.
(4) Read pressures on both gauges as throttle lever
on transaxle is moved from full clockwise to the full
counterclockwise position.
(5) Line pressure should read 52 to 58 psi with
throttle lever clockwise. Pressure should gradually
increase to 80 to 88 psi. as lever is moved counter-
clockwise.
(6) Kickdown release is pressurized only in direct
drive and should be same as line pressure within 3
psi, up to kickdown point.
(7) This tests pump output, pressure regulation,
and condition of rear clutch, front clutch, and
hydraulic circuits.
TEST FOUR (SELECTOR IN REVERSE)
(1) Attach 300 psi gauge (C-3292SP) to low-reverse
port.
(2) Operate engine at 1600 rpm for test.
(3) Move selector lever on transaxle four detents
forward from full rearward position. This is selector
R position.
(4) Low/reverse pressure should read 180 to 220
psi with throttle lever clockwise. Pressure should
gradually increase to 260 to 300 psi. as lever is
moved counterclockwise.
(5) This tests pump output, pressure regulation,
and condition of front clutch and rear servo hydraulic
circuits.
(6) Move selector lever on transaxle to D position
to check that low/reverse pressure drops to zero.
(7) This tests for leakage into rear servo, due to
case porosity, which can cause reverse band burn out.
TEST RESULT INDICATIONS
(1) If proper line pressure, minimum to maximum,
is found in any one test, the pump and pressure reg-
ulator are working properly.
(2) Low pressure in D, 1, and 2 but correct pres-
sure in R, indicates rear clutch circuit leakage.
(3) Low pressure in D and R, but correct pressure
in 1 indicates front clutch circuit leakage.
(4) Low pressure in R and 1, but correct pressure
in 2 indicates rear servo circuit leakage.
Fig. 2 Governor Pressure Tap
1 - GOVERNOR PRESSURE PLUG
RSAUTOMATIC - 31TH21-33
AUTOMATIC - 31TH (Continued)

(12) Remove front mount and bracket (Fig. 11).
(13) Cut transaxle oil cooler lines flush with fit-
tings. a service kit will be installed upon reintalla-
tion. Plug lines and fittings to prevent debris
intrusion.
(14) Remove structural collar (Fig. 12).
(15) Disconnect vehicle speed sensor connector.
(16) Remove rear mount shield (Fig. 13).
(17) Remove rear mount thru-bolt.
(18) Support engine with screw jack and wood
block.
(19) Remove cradle plate.
(20) Remove torque converter-to-drive plate bolts.
(21) Remove left wheel splash shield.
(22) Remove left upper mount thru-bolt (Fig. 14).
(23) Lower engine/transaxle assembly.
(24) Obtain transmission jack and helper.
(25) Remove remaining transaxle-to-engine bolts
and remove transaxle assembly from vehicle.
Fig. 11 Front Mount and Bracket
1 - BRACKET - FRONT MOUNT
2 - NUT
3 - BOLT
4 - MOUNT - FRONT INSULATOR
5 - BOLT
6 - BOLT
7 - FRONT CROSSMEMBER
Fig. 12 Structural Collar
1 - BOLT - COLLAR TO OIL PAN
2 - BOLT - COLLAR TO TRANSAXLE
3 - STRUCTURAL COLLAR
4 - OIL PAN
Fig. 13 Rear Mount Heat Shield
1 - BOLT - HEAT SHIELD
2 - HEAT SHIELD
3 - CLIP
4 - REAR MOUNT
21 - 38 AUTOMATIC - 31THRS
AUTOMATIC - 31TH (Continued)