check transmission fluid 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 ± Troubleshooting23-6
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 ± On-vehicle Service23-19
CONVERTER STALL TEST 23100540138
In this test, the engine maximum speed when the
torque converter stalls with the shift lever in the
ªDº or ªRº range is measured to check operation
of the torque converter, starter and one-way clutch
and check holding performance of the transmission
clutch (including brake).
Caution
Do not stand in front or at rear of the vehicle
during this test.
(1) Check the transmission fluid level. The fluid
temperature should be at the level after normal
operation (70 ± 80
C). The engine coolant
temperature should also be at the level after
normal operation (80 ± 90
C).
(2) Apply chocks to the rear wheels (right and left).
(3) Mount an engine tachometer.
(4) Apply fully the parking and service brakes.(5) Start the engine.
(6) With the selector lever in the ªDº range, fully
depress the accelerator pedal and read off the
engine maximum speed.
Standard value:
2,100 ± 2,400 r/min <4G63>
2,300 ± 2,600 r/min <4D56>
NOTE
When doing so, do not keep the engine running
with throttle full open for more than 5 seconds.
If two or more stall tests are needed, place
the selector lever in the ªNº position and run
the engine at about 1,000 r/min to allow the
transmission fluid to cool before another stall
test.
(7) Place the selector lever in the ªRº range and
perform the test as above.
JUDGEMENT OF STALL TEST RESULTS
Stall speed in ªDº and ªRº range is equal to each other
but lower than the nominal value.(1) Engine output is low.
(2) Starter one-way clutch is faulty. (Faulty torque
converter is suspected if it is lower than nominal
by more than 600 r/min)
Stall speed in ªDº range is higher than nominal.(1) Overdrive clutch slipping
(2) Overdrive one-way clutch faulty
(3) Forward clutch slipping
(4) One-way clutch No. 2 faulty
(5) Low line pressure
Stall speed in ªRº range is higher than nominal.(1) Overdrive clutch slipping
(2) Overdrive one-way clutch faulty
(3) Direct clutch slipping
(4) Brake No. 3 slipping
(5) Low line pressure