1991 MITSUBISHI 3000GT Service Manual

AUTOMATIC TRANSAXLE - Troubleshooting23-37
i
Continuity exists
/’
b
In the “R” range, check for con-tinuity between terminals 4 and 7,and terminals 10 and 11.
Continuity exists,
(t}tinuity between termrnals 2 and 4,
L.Continuity exists
4
In the
ti D“ range, check for con-tinuity between terminals 4 and 6.
c
+
Continuity exists\I
In the “2” range, check for con-
tinuity between terminals 1 and 4.
gzizkzgtinuity between terminals 4 and 5.
c
4
Continuity exists-I
NormalI
No continuity
/ P$f the inhibitor/
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23-38AUTOMATIC TRANSAXLE - Troubleshooting
12. Kickdown
(K/D) servo
switch
19=111
TFAO389
Check for continuity between thePoor contact, or dam-
kickdown servo switch terminalaged or disconnected
and the transaxle case.wiring
+c
Continuity existsReplace the K/D servo
+switch.
Start the engine, set to the “L”range, and let the engine idle;check for continuity between thekickdown servo switch terminalPoor contact (sticking)
and the transaxle case.
NOTE: Be sure the brakes are
applied during this check.4
+Replace the K/D servo
No continuityswitch.
+I
NormalIr
Disconnect the harness (both A
13. Transaxle con-and B connectors) from the vehi-
trol unit(TCU)cle’s TCU. Then connect, via an
intermediate harness for check-
ing, a new TCU to this harness
and make a road test.4
Install a new TCU.
Consider the original TCU to be
normal, and again check the sen-sors. wiring, etc.
4
Same problem (as before TCU
exchange) occurs.
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AUTOMATIC TRANSAXLE - Troubleshooting23-39
//!’ 6Rear@FrontclutchpressureI
@Kickdown brakeoressure (Release)
e
OIL PRESSURE TESTS1. Completely warm up the transaxle.
2.Raise the vehicle by using a jack so that the front wheels
can be rotated.
3. Connect an engine tachometer and place it in a position
where it’s easy to see.
4. Attach the special oil-pressure gauge (MD998330-01) and
the adaptor (MD998332-01) to each oil-pressure outlet port.
When the reverse pressure is to be tested, the 3,000
kPa(400 psi) type of gauge should be used.
5. Measure the oil pressure under various conditions, and
check to be sure that the measured results are within the
standard value range shown in the “Standard oil pressure
table” below.
If the oil pressure is not within the specified range, check
and repair as described in the section “Remedial steps if oil
pressure is not normal” on the next page.
STANDARD OIL PRESSURE TABLECondtttonsStandard
011 pressurekPa (PSI)No
SelectEngme
Red&g@000E%00leverspeedGearK/D brakeWD brakeFrontRearLow-TorqueposItlollvposltlon
pressurepressurepressureclutchclutchclutchreverseconverter
(application)(release)
pressurepressurepressurebrakepressure
pressure
1Nldlmg
Neutral
360 - 4808,(51 - 6812
Dldlmg
2nd
360
- 480100-210
730 -830k(51 - 68)
(14-30)
(104 -118)
3(SWFON,
Approx.
4th
360 480
830
-900
830
900
450-650
2,500(51 - 68) (118 128)(118 128)(64 92)
(SWZFF)Approx.
3rd
360 - 480
830
900830 -900 830 - 900
830 -900830
900
450-4
650-2.500(51 - 68)
(118
128)(118 -128) (118 - 128)
(118
128)(118128)
(64-921
52
Approx.
2nd
360
- 480
830--900
830 -900
450
650
2,500
(51 - 68)
(118-128)
(118 -128)
(64-921
Approx
1 st360 480
830 -900
300-450A1.000(51 - 68)
(118 -128)I43 .-64)
Approx.
Reverse
360 480
1.6402.2401.640 2.2401.640 -2.240450-6502.500(51 - 68)(233 - 319) (233 319)(233 319)(64 ~- 921
Approx.
Reverse
360
- 4801.500(213) 1.500 (213)1.500(213)
450~-650
1,000(51 - 68)or moreor moreor more(64 - 92)NOTE
(I)
-: Indicates pressure is below 10 kPa (1.4 psi).
(2)SW-ON: OD switch in ON position.
(3)SW-OFF: OD switch in OFF position.
(4)
a: Pressure IS not standard.
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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
‘\
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

23-42AUTOMATIC TRANSAXLE - Troubleshooting.
SHIFT PATTERNSP range
-i;a-n 60
.rs
8
-z" 405
-+-!
34(b)
2413(2,L)
IIII
100020003000400050006000Transferdrivegearspeedtrpm)
IIIIIIIIIIIIIIIIIIII
010203040
5060708090
100110
120130140150160170180
Vehiclespeed (km/h)TFA0570E range
IOC
80-z
6
F60'E4
$40
5E
20
0
I3 e-4 (DAI
200030004000
50006000Transferdrivegearspeed
(rpm)
IIIIIIIIIIII
IIIIIIII010203040
5060
708090100110120130140150160170
180
Vehiclespeed (km/h)
T FA0571
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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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