MITSUBISHI TRITON 1997 Workshop Manual

AUTOMATIC TRANSMISSION ± Troubleshooting23-4
TROUBLESHOOTING23100760152
STANDARD FLOW OF DIAGNOSIS TROUBLESHOOTING
Automatic transmission malfunctions may be caused by the following conditions.
(1) Improper maintenance and adjustment
(2) Shift control system malfunction
(3) Mechanical malfunctions
(4) Hydraulic malfunctions
(5) Poor engine performance
Troubleshooting in the event of any such malfunctions should begin by checking fluid level, ATF condition,
manual linkage adjustment, throttle control cable adjustment and other conditions whose deviation from
standards can be readily known. Then, road test shall be performed to determine whether or not the
problem has been corrected or more diagnosis is necessary. If the problem still persists after these tests
and corrections, hydraulic tests should be performed for further troubleshooting.
Road test (guess what causes malfunc-
tion.)
Check how A/T works in each drive
range to find a defective system.
A/T control component inspection
Check the throttle cable, inhibitor switch,
overdrive switch, overdrive solenoid
valve, overdrive control relay, defective
switch, engine coolant temperature
switch and vehicle speed sensor.
Torque converter stall test (Inspection
of engine performance and mechanical
function)
Check the engine performance, torque
converter operation and clutch and
brake sliding performance.
Hydraulic pressure test (Inspection of
hydraulic control mechanism)
Measure the fluid line pressure and
check for malfunctions of the oil pump
or regulator valve and for oil leaks.
Oil leak inspection
Visually check gaskets and oil seals for
leaks.
Adjustment of basic inspection items
ROAD TEST 23100780158
Prior to performing road test, be sure to make basic checks including check and adjustment of fluid
level and condition and adjustment of the throttle cable. For road test, the transfer must be placed in
the 2H (2WD-high) position. In road test, various changes such as slips in transmission and shifting
conditions are checked and the transmission operation at each shift position must have been checked.

AUTOMATIC TRANSMISSION ± Troubleshooting23-5
D RANGE TEST
Correct
Carry out the TEST 1 again.
Ye s
Check the shifting points.Incorrect
Line pressure malfunction

Governor malfunction

Incorrect throttle cable adjustment
Ye s
Does the upshift from 3-speed to 4-speed occur? (with throttle
valve opening under 85%)No
3 ± 4 shift valve malfunction

Governor malfunction

Overdrive switch or overdrive solenoid malfunction

Overdrive control relay malfunction

Engine coolant temperature switch malfunction <4G6>
Ye s
Does the upshift from 2-speed to 3-speed occur?No
2 ± 3 shift valve malfunction

Governor malfunction
NG
Does the upshift from 1-speed to 2-speed occur?No
1 ± 2 shift valve malfunction

Governor malfunction
TEST 1
Start with throttle valve opened (50 % and full), and check upshift
from 1-speed  2-speed, 2-speed 3-speed and 3-speed 
4-speed. Check that shifting points match shift pattern.OKTEST 2
Correct
Carry out TEST 2 again.
Ye s
Check the shifting point.Incorrect
Line pressure malfunction

Governor malfunction

Detent regulator valve malfunction
NG
Does the downshift occur?No
Shift valves malfunction

Governor malfunction

Overdrive switch or overdrive solenoid malfunction

Overdrive control relay malfunction

Detection switch malfunction
TEST 2
Kickdown traveling at 2-speed, 3-speed and 4-speed. Check that
possible kickdown vehicle speed limit at 2-speed  1-speed,
3-speed  1-speed, 3-speed  2-speed, or 4-speed  1-speed,
4-speed  2-speed, 4-speed  3-speed conforms with the shift
pattern.OKTEST 3
Correct
Carry out TEST 3 again.
Ye s
Check the Shifting point.Incorrect
Incorrect throttle cable adjustment

Governor malfunction

Line pressure malfunction

Low coast modulator valve malfunction
NG
Does the downshift from 2-speed to 1-speed occur?No
1 ± 2 shift valve malfunction

Governor malfunction
TEST 3
When traveling in 3-speed or 4-speed, release accelerator pedal
and shift to L. Check that 3-speed  2-speed or 4-speed  3-speed
takes place immediately and 2-speed  1-speed downshift con-
forms with shift pattern.OKTEST 4

AUTOMATIC TRANSMISSION ± Troubleshooting23-6
Ye s
Carry out TEST 4 again.
Ye s
Does the engine brake function in L range?NoBrake No. 3 malfunction
No
Does the engine brake function in 2 range?NoBrake No. 1 malfunction
TEST 4
When traveling in 3-speed or 4-speed, shift to 2 and L. Does the
engine brake function in each range?Ye sTEST 5
Ye s

High line pressure

Accumulator malfunction

Check ball malfunctionCarry out TEST 5 again.
TEST 5
Is there abnormal noise(s) during acceleration and deceleration?
Is there shocks when slipping and changing speed?NoTEST 6
Ye s

Incorrect torque converter installation

Oil pump malfunction

Shifting gear not meshing correctly

Incorrect drive plate installationCarry out TEST 6 again.
TEST 6
Is there abnormal noise(s) or vibration when traveling in 3-speed
or 4-speed?NoTEST 7
NOTE
Abnormal noises and vibrations are often caused by an unbalanced propeller shaft, differential, tyre,
torque converter, engine, etc. Extremely thorough inspection is therefore required.
Ye s
Carry out TEST 7 again.
Ye s
Does lock up go on, off?No
Lock up signal valve malfunction

Lock up relay valve malfunction

Lock up clutch malfunction
No
Does the moment when lock up turns ON or OFF conform with
the shift pattern?No
Governor malfunction

Line pressure malfunction
TEST 7
Check that lock up ON, OFF. Does the shifting points conform
with shift pattern?Ye sCarry out the road test in 2 range.
NOTE
(1) Determine the moment when lock up turns ON by decreased engine r/min or by a slight shock back
and forth.
(2) Determine the moment when lock up turns OFF by increased engine r/min.
(3) Check lock up condition by pumping the accelerator slightly. If engine r/min rises in accordance with
throttle valve opening size, determine that the lock up is OFF, if not, determine it ON.
(When lock up is OFF, drive power is transferred through the fluid in the torque converter and therefore,
when the accelerator pedal is depressed, slipping occurs inside the torque converter with a resulting
large increase in engine r/min.)

AUTOMATIC TRANSMISSION ± Troubleshooting23-7
2 RANGE TEST
Correct
Carry out TEST 1 again.
Ye s
Check the shifting point.Incorrect
Misadjusted throttle cable

Governor malfunction

Line pressure malfunction
No
Does the upshift from 1-speed to 2-speed occur?No
1 ± 2 shift valve malfunction

Governor malfunction
TEST 1
Start with throttle valve opening at 50% and full. Does the shifting
points conform with the shift pattern when upshifting from 1-speed

2-speed?Ye sTEST 2
Ye s
Carry out TEST 2 again.
NG
Does the downshift occur and is the shifting point correct?No
Detent regulator valve malfunction

Governor malfunction

Misadjusted throttle cable

1 ± 2 shift valve malfunction

Line pressure malfunction
TEST 2
Kickdown and check that possible kickdown vehicle speed limit
at 2-speed
1-speed conforms with shift pattern.OKCarry out road test in L range.
L RANGE TEST
No
Carry out road test in R range.
TEST 1
Does the transmission upshift to 2-speed?Ye s
Low coast modulator valve malfunction

Governor malfunction

Low line pressure
R RANGE TEST
Ye s
Carry out road test in P range.
TEST 1
Is the engine r/min by stall test correct?No
Brake No. 3 malfunction

Overdrive clutch or direct clutch malfunction

Overdrive one-way clutch malfunction

Low line pressure
P RANGE TEST
Ye s
End
TEST 1
Park vehicle on an incline (more than 5) and release parking
and service brakes. Does the vehicle move?No
Park mechanism malfunction

Misadjusted shift lever

2 3
2 2
4000 5000 T
hro ttle o penin g (
% ) L
ock-u p O N L
ock-u p O FF O
utp ut s h aft s p eed r /m in V
ehic le s p eed k m /h
1
000 2000
3000
1
00
8 0
6 0
4 0
2 0
0 0 20
1 0 30 40 50 60 70
80 90 100
120
1 1 0
2
3 4
1 3
4
2
3
1
1
< 4D 56 e n gin e> 32
22(
% ) L
ock-u p O N L
ock-u p O FF O
utp ut s h aft s p eed r /m in V
ehic le s p eed k m /h 4
000
1
000 2000
3000
1
00
8 0
6 0
4 0
2 0
0
0 20
1 0 30 40 50 60 70
80
90 100
120
1 1 0
2
34
1 3
4
2 3
1
1
130
1

I
n sp ectio n it e m C
heck r e quir e m ent S
ta ndard v a lu e 2 O
ve rd riv e s
w it c h I
g nit io n s w it c h : O N O
ve rd riv e s w it c h : O FF S
yste m v o lt a ge s
w it c h O
ve rd riv e s w it c h : O N 0
V 3 I
g nit io n s w it c h I
g nit io n s w it c h : O FF 0
V I
g nit io n s w it c h : O N S
yste m v o lt a ge 4 D
ete ctio n s w it c h R
un th e v e hic le T
hro ttle v a lv e : c o nsta nt
o penin g ( u nder 8 5 % ) S
yste m v o lt a ge T
hro ttle v a lv e : F ull o penin g 0
V 5 O
ve rd riv e
s o le noid v a lv e R
un th e v e hic le a t 5 0 k m /h
O ve rd riv e s w it c h : O N T
hro ttle v a lv e : c o nsta nt
o penin g ( u nder 8 5 % ) 0
V T
hro ttle v a lv e : F ull o penin g 1
1 V o r m ore 6 E
arth A
lw ays 0
V 7 E
ngin e c o ola nt t
e m e
ra tu re I
g nit io n s w it c h : O N 3
0
C o r lo w er S
yste m v o lt a ge t
e m era tu re 6
0
C o r h ig her 0
V 8 V
ehic le s p eed
s e nso r I
g nit io n s w it c h : O N
M ove th e v e hic le s lo w ly fo rw ard 0
V e 5 V
( C hanges r e peate dly )

O
N-V EH IC LE S ER VIC E 23100090121
A UTO M ATIC T R ANSM IS SIO N F LU ID C HEC K
1 . Pla ce th e v e hic le o n a le ve l s u rfa ce .
2 . Befo re r e m ovin g th e d ip stic k, w ip e a ll d ir t fr o m a re a a ro und
t h e d ip stic k.
3 . Wit h th e s e le cto r le ve r in th e ª P º p osit io n a nd th e p ark in g
b ra ke a pplie d, s ta rt th e e ngin e.
4 . The e ngin e s h ould b e r u nnin g a t id le a nd th e tr a nsm is sio n
s h ould b e w arm ed u p s u ff ic ie ntly . ( flu id te m pera tu re 7 0
± 8 0
C )
5 . Move th e s e le cto r le ve r th ro ugh a ll p osit io ns to fill th e
t o rq ue c o nve rte r a nd h yd ra ulic c ir c u it w it h flu id . T hen
p la ce th e le ve r in th e ª N º p osit io n.
6 . Check th at flu id le ve l is a t o il le ve l g auge ª H O Tº. If flu id
l e ve l is lo w , a dd flu id to ª H O Tº le ve l.
T ra n sm is sio n f lu id : D EXR O N-I I o r e q uiv ale n t
N O TE
L ow flu id le ve l c a n a llo w th e o il p um p to ta ke in a ir to geth er
w it h flu id , le adin g to v a rio us tr o uble s. A ir tr a pped in
h yd ra ulic c ir c u it fo rm s b ubble s w hic h m ake th e flu id
s p ongy. T his lo w ers p re ssu re a nd s h ow s d ow n p re ssu re
b uild up. If th e tr a nsm is sio n h as to o m uch flu id , g ears
c h urn u p fo am a nd c a use s a m e c o ndit io ns a s w hen th e
f lu id le ve l is lo w , r e su lt in g in p re m atu re d ete rio ra tio n o f
A T F. In e it h er c a se , a ir b ubble s c a n c a use o ve rh eatin g
a nd flu id o xid atio n a nd v a rn is h in g, w hic h c a n in te rfe re
w it h n orm al v a lv e , c lu tc h a nd s e rv o o pera tio n. F oam in g
c a n a ls o r e su lt in flu id e sca pin g fr o m th e tr a nsm is sio n
v e nt w here it m ay b e m is ta ke n fo r a flu id le ak.
7 . Check flu id c o ndit io n.
N O TE
W hen flu id s m ells b urn ed, it is c o nta m in ate d w it h m eta l
b ush in g o r fr ic tio n m ate ria l p artic le s a nd h ence a c o m ple te
o ve rh aul o f th e tr a nsm is sio n is n eeded. B e s u re to
e xa m in e flu id o n th e d ip stic k c lo se ly .
8 . Afte r flu id h as b een c h ecke d, in se rt th e d ip stic k u ntil it
i s s e ate d fu lly to s e al o ut w ate r a nd d ir t. C
O LD
u pper lim it H
O T
l o w er lim it H
O T
u pper lim it

C
O LD
u pper lim it H
O T
l o w er lim it H
O T
u pper lim it F
ille r p lu g h ole O
il le ve l

T
e rm in al N o. 1 2
2
H 4
H T
e rm in al N o. 1 2
4
H 4
L 4
H ± 4 L O
il fille r p lu g

D
ust c o ve r I
n ner c a ble s to pper A
dju stin g n ut O
ute r c a ble
3 4 ± 3 5 m m A
dju stin g n ut