1991 MITSUBISHI 3000GT brake

23-40AUTOMATIC TRANSAXLE - Troubleshooting
REMEDIAL ACTION TO TAKE FOR INADEQUATE OIL PRESSURESymptom
Possible cause
Remedy
1. All line pressuresa. Plugged oil filter
are low (or high).b. Improperly adjusted regulatora. Visually check oil filter and replace it if plugged.
valve line pressure
b. Measure line pressure (2) (KID brake pres-
NOTE:sure) and readjust line pressure if it is
Line pressures areout of specifications.
@.@.@).@.@and @shown onc. Defective valve body assemblyOr, replace valve body assembly.
the Standard Oil
Pressure Table
on the preceding
paw.
d. Valve body left loose
e. Improper oil pump delivery.
pressurec. Replace valve body assembly.d. Torque valve body clamp bolt and mounting
bolt to specification.
e. Check oil pump gear side clearance and
replace oil pump assembly as necessary.
2. Improper reducing
a. Plugged reducing pressure
a. Disassemble valve body assembly to check
pressurecircuit filter (L-shaped)
b. Improperly adjusted reducingfilter and replace filter if it is plugged.
b. Measure reducing pressure @and readjust
pressure
c. Defective valve body assemblyas necessary.
c. Replace valve body assembly.
3. Improper K/D
brake pressure
(application)a. Defective seal ring
@ and D-ring @of K/D servo piston and seal ringa. Disassemble K/D servo and check seal ring
@of sleeveand D-ring for damage. Replace seal ringb. Defective valve body assemblyor D-ring if damaged or scratched.
b. Replace valve body assembly.
4. Improper KIDbrake pressure
(release)
J. Improper front
clutch pressurea. Defective seal ring
@ and D-ring @of K/D servo piston and seal ringa. Disassemble KID servo and check seal ring
@ of sleeveand D-ring for damage. Replace seal ring
b. Defective valve body assemblyor D-ring if damaged or scratched.b. Replace valve body assembly.
a. Defective seal ring @and D-ring
@of K/D servo piston and seal ringa. Disassemble K/D servo and check seal ring
@ of sleeveand D-ring for damage. Replace seal ringb. Defective valve body assemblyor D-ring if damaged or scratched.
c. Worn front clutch piston andb. Replace valve body assembly.c. Disassemble transaxle and check front clutch
retainer or defective D-ring @or seal ring @piston and retainer for wear and D-ring and
seal ring for damage. Replace piston, retainer,
D-ring, or seal ring as necessary.
3. Improper
rear clutch
pressure
7. Improper
end clutch
pressurea. Defective D-ring
@ of piston,
seal ring @ of retainer,
and seal ring @and D-ring @of input shaft
b. Defectrve valve body assembly
a. Defective seal ring
0. D-ring 0,and oil seal (iJ of end clutch
b. Defective valve body assemblya. Disassemble rear clutch and check input shaft
D-ring, center support seal ring, and piston
D-ring; replace if damaged or scratched.
b. Replace valve body assembly.
a. Disassemble the end clutch and check piston oil
seal, D-ring, and center support seal ring;
replace if damage or scratches are evident.
b. Replace valve body assembly.
8. Improper
low-reverse
brake pressurea. Damaged O-ring between valve
body and transmission
b. Defective valve body assemblyc. Defective D-ring @of piston
or O-ring
@I of center supporta. Remove valve body assembly and check O-ring
on top of upper valve body; replace if damage
or scratches are evident.
b. Replace valve body assembly.
c. Disassemble transaxle and check D-ring and
O-ring; replace if damage or scratches are eviden
3. Improper
torque converter
pressurea. Sticking damper clutch controla. Check damper clutch system and DCCSV
solenoid valve (DCCSV) or damper
for operation.
clutch control valve
b. Plugged or leaky oil cooler and
pipingsb. Repair or replace cooler or pipings.
c. Damaged seal ring @of input shaftc. Disassemble transaxle and check seal ring;
d. Defective torque converterreplace if it is damaged.
d. Replace torque converter.
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d
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d

AUTOMATIC TRANSAXLE - Troubleshootina23-41
L-l@Seal ring
$&-g&J\@Seal ring@I O-ring!A>. .Yr&w
\
@ 011 seal
h.43 D-ring@ D-rmgA\ring
/@I Seal ring@Seal rmgI
Front clutchI@Seal
rmg
rItna cIuIcn
Low-reverse brake
TFA0641
@Seal ring
/
TFA0362TSB Revision

AUTOMATIC TRANSAXLE - Troubleshootinn23-43
CONVERTER STALL TESTStall test consist of determining maximum engine
speed obtained at full throttle in “D” and
“I?”positions. This test checks torque converter
statoroverrunning clutch operation, and holding ability of
transaxle clutches and low-reverse brake.
Caution
During this test, make sure that no one stand in
front of or behind vehicle.
1. Check transaxle fluid level. Fluid should be at
normal operating temperature
[70 - 80°C (160 -
18O”F)I. Engine coolant should also be at normal
operating temperature
[80 - 90°C (180 - 19O”F)l.2. Apply chocks to both rear wheels.
3. Attach engine tachometer.
4. Apply parking and service brakes fully.
5. Start engine.
6. With selector lever in “D” position, depress
accelerator pedal fully to read engine maximum
rpm. Do not hold throttle wide open any longer
than is necessary to obtain maximum engine
rpm reading, and never longer than 5 seconds at
a time. If more than one stall test is required,
operate engine at approximately 1,000 rpm in
neutral for 2 minutes to cool transaxle fluid
between tests.
Stall speed: 2,200
- 3,200 rpm
7.Place selector lever to “R” position and perform
stall test by the same procedure as in foregoing
item.
Stall Speed Above Specification in “D”
If stall speed is higher than specification, rear clutch
or overrunning clutch of transaxle is slipping. In this
case, perform hydraulic test to locate cause of
slippage.
Stall Speed Above Specification in “R”
If stall speed is higher than specification, front
clutch of transaxle or low-reverse brake is slipping.
In this case, perform hydraulic test to locate cause
of slippage.
Stall Speed Below Specification in “D” and “R”
If stall speed is lower than specification, insufficient
engine output or faulty torque converter is sus-
pected. Check for engine misfiring, ignition timing,
valve clearance, etc. If these are good, torque
converter is faulty.
TRANSAXLE CONTROL
Symptom
Selector lever operationis stiff
Probable cause
Incorrect adjustment of sleeve
Remedy
Adjust
Incorrect adjustment of control cable
Excessive wear of detent plate
Worn contact surfaces of pushbutton
and sleeve
Adjust
Replace
Replace
Starter motor does notMalfunction in inhibitor switchReplace
operate with the selector
lever in the “N” or “P”Incorrect adjustment of control cableAdjust
position
Will not shift to
4-speed
Malfunction of starter relay
Malfunction of OD switchReplace
Replace
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23-44AUTOMATIC TRANSAXLE - Troubleshootina
A/T SAFETY-LOCK SYSTEM TROUBLESHOOTINGbe selectedinto
Rfrom P by depressing
brake pedal with
ignition key in
position other than
LOCK.n or sagging outer cable(shift
loteck andadjust slide lever
ide lever and ca
Selector lever
Iperation from P to Rs not smooth.
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23-46AUTOMATIC TRANSAXLE - Service Adjustment Procedures
Fluid level must be
within this range.
TFA038:
SERVICE ADJUSTMENT PROCEDURE!5
MZ3FElBJ
TRANSMISSION FLUID LEVEL INSPECTION
1.Drive until the fluid temperature reaches the usual tempera-
ture
170 - 80°C (160 - 18O”F)].2. Place vehicle on level floor.
3. Move selector lever sequentially to every position to fill
torque converter and hydraulic circuit with fluid, then place
lever in “N” Neutral position.
4. Before removing dipstick, wipe all dirt from area
arouniddipstick. Then take out the dipstick and check the condition
of the fluid.
The transaxle should be overhauled under the following
conditions.
’ l If there is a “burning” odor.
l If the fluid color has become noticeably blacker.
lIf there is a noticeably great amount of metal particles in
the fluid.
5.Check to see if fluid level is in “HOT” range on dipstick. If
fluid level is low, add automatic transmission fluid until level
reaches “HOT” range.
Transmission fluid: MITSUBISHI PLUS ATF/Automatictransmission fluid “DEXRON”
abr“DEXRON II”
Low fluid level can cause a variety of conditions because it
allows pump to take in air along with fluid. Air trapped in
hydraulic circuit forms bubbles which make fluid spongy.
Therefore, pressures will be erratic, causing delayed shift,
slippy clutch and brakes, etc.
Improper filling can also raise fluid level too high. When
transaxle has too much fluid, gears churn up foam
anldcause the same conditions which occur with low fluid level,
resulting in accelerated deterioration of automatic
transaxllefluid.
In either case, air bubbles can cause overheating, fluid
oxidation, which can interfere with normal valve, clutch, and
servo operation. Foaming can also result in fluid escaping
from transaxle vent where it may be mistaken for a leak.
6. Be sure to examine fluid on dipstick closely.
TRANSMISSION FLUID REPLACEMENTM23FCBHRefer to GROUP 00
- Maintenance Service.
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AUTOMATIC TRANSAXLE - Service Adjustment Procedures23-47
MD998916-3-01
KICKDOWN SERVO ADJUSTMENTM23FRAC(1) Remove dust, dirt, and other contaminants completely fromkickdown (K/D) servo cover and surrounding areas.
(2) Snap off the snap ring and remove K/D servo switch.
(3) Fit claw of special tool into cutout in piston to prevent
piston from turning and use adapter to fix the piston into
position.
Caution
1. Do not push piston with the special tool.
2.Secure adapter only hand-tight to L/R brake press-
ure take-up port and do not apply
excessiwe torque.
(4) Loosen lock nut to immediately before V-groove in adjust
rod (see illustration on left) and tighten special tool (Inner
Wrench) until it contacts lock nut.
(5) Fit special tool (Outer Wrench) over the lock nut. Turn Outer
Wrench counterclockwise and turn inner cylinder clockwise
to lock the lock nut and special tool (Inner Wrench).
(6) Fit torque wrench to special tool (Inner Wrench) and repeat
tightening and loosening cycle two times with a torque of
10 Nm (7.2 ft.lbs.). Then, torque to 5 Nm (3.6 ftlbs.).Next, back off special tool (Inner Wrench) 2 to
2’/4 turns.
(7) Fit special tool (Outer Wrench) to lock nut.
Turn Outer Wrench clockwise and Inner Wrench counter-
clockwise to unlock the lock nut from special tool (Inner
Wrench).
Caution
Be sure to apply even torque to the two special tools
when unlocking.
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23-48AUTOMATIC TRANSAXLE - Service Adjustment Procedures
Adjusting screw4
or~0\====m00~7/IIIITFAm
c-1
Pi(8) Tighten lock nut by hand until it contacts piston. Then, using
torque wrench, tighten to specification.
Lock nut: 29 Nm (21
ftlbs.)Caution
Use of socket wrench or torque wrench could result in
lock nut being turned with adjust rod.
(9) Remove the special tool to secure the piston and torque
plug to specification at L/R brake pressure take-up port.
LINE PRESSURE ADJUSTMENT
(I) Discharge AFT.
(2) Remove oil pan.
(3) Remove oil filter.
(4) Remove oil temperature sensor.
M23FSAC(5) Press solenoid valve harness grommet catch to push in
grommet; then, remove valve body assembly.
Caution
Do not let manual valve fall.
(6) Turn adjusting screw of regulator valve to obtain the
specified line pressure
(K/D brake pressure).
Standard value:870
- 890 kPa (124 - 127 psi)
Oil pressure change for
each turn of adjustment screw:38
kPa (54 psi)
(7)Check that an O-ring is fitted at the location shown on top off
valve body.
(8) Replace O-ring of solenoid valve intermediate grommet
with a new one and then fit the O-ring into case.6
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AUTOMATIC TRANSAXLE - Service Adjustment Procedures23-49
1(9) Install valve body and oil temperature sensor.
Bolt A
= Length 18 mm (.709 in.)
Bolt B
= Length 25 mm (.984 in.)
Bolt C
= Length 40 mm (1.575 in.)
CautionSecure solenoid valve and oil temperature sensor
harness at locations shown.
(1O)lnstall oil filter.(1l)lnstall new oil pan gasket and oil pan.
(12)Add the specified amount of ATF.
(13)Carry out hydraulic test.
Readjust as necessary.
REDUCING PRESSURE ADJUSTMENTh323FfADWhen multi-use tester is not used
(1) Following the same steps as those in line pressure
adjustment, remove parts up to oil filter.
There is no need to remove valve body.
(2) Turn adjusting screw of lower valve body to obtain the
specified reducing pressure. Turn it counterclockwise to
increase the pressure.
Standard value:425 f 10 kPa (60 f 1 psi)
Oil pressure change for
each turn of adjusting screw:45 kPa (6 psi)(3) In the same way as in line pressure adjustment,
/nstall oil
filter and oil pan.
(4) Perform hydraulic test.
Adjust as necessary.
When multi-use tester is used
(1) Adjust to obtain the specified K/D brake pressure when PC
solenoid is energized at duty 50% with the multi-use tester.
Standard value:275 kPa (39 psi)
Oil pressure change for
each turn of adjusting screw:50 kPa (7 psi)(2) After adjustment has been made, check that the recuding
pressure is in the range 360
- 480 kPa (51 - 68 psi).
Caution
This adjustment should be made with oil temperature70
- 80°C (160 - 180°F).
The adjustment made with high oil temperature couldresult in improper adjustment due to a line pressure
drop at idle.
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