Page 2993 of 4284

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)
Page 2994 of 4284

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)
Page 2995 of 4284

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)
Page 2996 of 4284

The process of elimination can be used to detect
any unit that slips and to confirm proper operation of
good units. Road testing can usually diagnose slip-
ping units, although the actual cause of the problem
may not be detected. Practically any condition can be
caused by leaking hydraulic circuits or sticking
valves.
Therefore, unless the condition is obvious, the
transaxle should never be disassembled until hydrau-
lic pressure tests have been performed.DIAGNOSIS AND TESTING - HYDRAULIC
PRESSURE TESTS
Pressure testing is a very important step in the
diagnostic procedure. These tests usually reveal the
cause of most transaxle problems.
Before performing pressure tests, check fluid level
and condition, as well as control cable adjustments.
Fluid must be at operating temperature (150-200
degrees F.).
Install an engine tachometer. Raise vehicle on a
hoist that allows front wheels to turn, and position
tachometer so it can be read.
Disconnect throttle cable and shift cable from
transaxle levers so they can be controlled from out-
side the vehicle.
Attach 100 psi gauges (C-3292) to ports required
for test being conducted. A 300 psi gauge (C-3293SP)
is required for reverse pressure test at rear servo.
Test port locations are shown in (Fig. 1).
Fig. 1 Test Port Locations
1 - ACCUMULATOR VENT
2 - MANUAL THROTTLE LEVER SHAFT
3 - MANUAL SHIFT LEVER SHAFT
4 - LOW-REVERSE PRESSURE
5 - GOVERNER PRESSURE (BELOW DIFFERENTIAL COVER
ON RIGHT SIDE)
6 - LINE PRESSURE
7 - KICKDOWN APPLY AT ACCUMULATOR8 - TO COOLER
9 - KICKDOWN RELEASE (FRONT CLUTCH)
10 - KICKDOWN APPLY
11 - CONVERTER CLUTCH SOLENOID CONNECTOR
12 - FROM COOLER
13 - KICKDOWN BAND ADJUSTING SCREW
21 - 32 AUTOMATIC - 31THRS
AUTOMATIC - 31TH (Continued)
Page 2997 of 4284

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)
Page 2998 of 4284

(5) Low line pressure in all positions indicates a
defective pump, a clogged filter, or a stuck pressure
regulator valve.
GOVERNOR PRESSURE
Test only if transaxle shifts at wrong vehicle
speeds when throttle cable is correctly adjusted.
(1) Connect a 100 psi gauge to governor pressure
port. It is located at lower right side of case, below
differential cover (Fig. 2).
(2) Operate transaxle in third gear to read pres-
sures. The governor pressure should respond
smoothly to changes in mph and should return to 0
to 3 psi when vehicle is stopped. High pressure
(above 3 psi) at standstill will prevent the transaxle
from downshifting.
THROTTLE PRESSURE
No gauge port is provided for throttle pressure.
Incorrect throttle pressure should be suspected if
part throttle upshift speeds are either delayed or
occur too early in relation to vehicle speed. Engine
runaway on shifts can also be an indicator of low
throttle pressure setting, or misadjusted throttle
cable.
In no case should throttle pressure be adjusted
until the transaxle throttle cable adjustment has
been verified to be correct.
DIAGNOSIS AND TESTING - TORQUE
CONVERTER HOUSING FLUID LEAKAGE
When diagnosing converter housing fluid leaks,
three actions must be taken before repair:
(1) Verify proper transmission fluid level.
(2) Verify that the leak originates from the con-
verter housing area and is transmission fluid.
(3) Determine the true source of the leak.
Fluid leakage at or around the torque converter
area may originate from an engine oil leak (Fig. 3).
The area should be examined closely. Factory fill
fluid is red and, therefore, can be distinguished from
engine oil.
Some suspected converter housing fluid leaks may
not be leaks at all. They may only be the result of
residual fluid in the converter housing, or excess
fluid spilled during factory fill, or fill after repair.
Converter housing leaks have several potential
sources. Through careful observation, a leak source
can be identified before removing the transmission
for repair.
Pump seal leaks tend to move along the drive hub
and onto the rear of the converter (Fig. 3). Pump
o-ring or pump body leaks follow the same path as a
seal leak. Pump attaching bolt leaks are generally
deposited on the inside of the converter housing and
not on the converter itself. Pump seal or gasket leaksusually travel down the inside of the converter hous-
ing (Fig. 3).
TORQUE CONVERTER LEAKAGE
Possible sources of torque converter leakage are:
²Torque converter weld leaks at the outside diam-
eter weld (Fig. 4).
²Torque converter hub weld (Fig. 4).
Fig. 3 Converter Housing Leak Paths
1 - PUMP SEAL
2 - PUMP VENT
3 - PUMP BOLT
4 - PUMP GASKET
5 - CONVERTER HOUSING
6 - CONVERTER
7 - REAR MAIN SEAL LEAK
Fig. 4 Converter Leak PointsÐTypical
1 - OUTSIDE DIAMETER WELD
2 - TORQUE CONVERTER HUB WELD
3 - STARTER RING GEAR
4 - LUG
21 - 34 AUTOMATIC - 31THRS
AUTOMATIC - 31TH (Continued)
Page 2999 of 4284

DIAGNOSIS AND TESTING - CLUTCH AND
SERVO AIR PRESSURE TESTS
A no drive condition might exist even with correct
fluid pressure, because of inoperative clutches or
bands. The inoperative units, clutches, bands, and
servos can be located through a series of tests. This
is done by substituting air pressure for fluid pressure
(Fig. 5).
The front and rear clutches, kickdown servo, and
low-reverse servo may be tested by applying air pres-
sure to their respective passages. To make air pres-
sure tests, proceed as follows:
NOTE: Compressed air supply must be free of all
dirt or moisture. Use a pressure of 30 psi.Remove oil pan and valve body. Refer to Valve
Body for removal procedure.FRONT CLUTCH
Apply air pressure to front clutch apply passage
and listen for a dull thud which indicates that front
clutch is operating. Hold air pressure on for a few
seconds and inspect system for excessive oil leaks.
REAR CLUTCH
Apply air pressure to rear clutch apply passage
and listen for a dull thud which indicates that rear
clutch is operating. Also inspect for excessive oil
leaks. If a dull thud cannot be heard in the clutches,
place finger tips on clutch housing and again apply
air pressure. Movement of piston can be felt as the
clutch is applied.
Fig. 5 Air Pressure Tests
1 - PUMP SUCTION
2 - PUMP PRESSURE
3 - FRONT CLUTCH APPLY
4 - REAR CLUTCH APPLY
5 - TO TORQUE CONVERTER
6 - FROM TORQUE CONVERTER
7 - TO OIL COOLER
8 - KICKDOWN SERVO OFF
9 - KICKDOWN SERVO ON10 - ACCUMULATOR OFF
11 - ACCUMULATOR ON
12 - LOW-REVERSE SERVO APPLY
13 - GOVERNOR PRESSURE
14 - LINE PRESSURE TO GOVERNOR
15 - GOVERNOR PRESSURE PLUG
16 - GOVERNOR PRESSURE
17 - BYPASS VALVE BORE
RSAUTOMATIC - 31TH21-35
AUTOMATIC - 31TH (Continued)
Page 3000 of 4284

KICKDOWN SERVO (FRONT)
Direct air pressure into KICKDOWN SERVO ON
passage. Operation of servo is indicated by a tighten-
ing of front band. Spring tension on servo piston
should release the band.
LOW AND REVERSE SERVO (REAR)
Direct air pressure into LOW-REVERSE SERVO
APPLY passage. Operation of servo is indicated by a
tightening of rear band. Spring tension on servo pis-
ton should release the band.
If clutches and servos operate properly, no upshift
indicates that a malfunction exists in the valve body.
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR
Damaged or worn threads in the aluminum trans-
axle case and valve body can be repaired by the use
of Heli-Coils, or equivalent. This repair consists of
drilling out the worn-out damaged threads. Then tap-
ping the hole with a Heli-Coil tap, or equivalent, and
installing a Heli-Coil insert, or equivalent, into the
hole. This brings the hole back to its original thread
size.
Heli-Coil, or equivalent, tools and inserts are
readily available from most automotive parts suppli-
ers.
REMOVAL
(1) Disconnect battery negative cable.
(2) Remove fluid level indicator tube bolt and tube/
indicator assembly (Fig. 6). Plug opening to prevent
debris intrusion.
(3) Disconnect torque converter clutch solenoid
(TCC) connector.
(4) Disconnect kickdown cable from lever and
bracket (Fig. 7). Position out of way.
(5) Disconnect gearshift cable from manual valve
lever and upper mount bracket (Fig. 8). Position out
of way.
(6) Disconnect back-up lamp switch connector.
(7) Remove upper two (2) transaxle-to-engine bolts.
(8) Remove three (3) rear mount bracket-to-trans-
axle case bolts (Fig. 9).
(9) Raise vehicle on hoist.
(10) Remove halfshafts. (Refer to 3 - DIFFEREN-
TIAL & DRIVELINE/HALF SHAFT - REMOVAL)
(11) Remove starter motor assembly (Fig. 10).
Fig. 6 Fluid Level Indicator Assembly
1 - INDICATOR ASSEMBLY
2 - BOLT
3 - KICKDOWN CABLE BRACKET
4 - SEAL
Fig. 7 Throttle Valve Cable at Transaxle
1 - LEVER
2 - BRACKET
3 - THROTTLE VALVE CABLE
21 - 36 AUTOMATIC - 31THRS
AUTOMATIC - 31TH (Continued)