Mitsubishi Montero Sport (2004+). Manual - part 615

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

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TORQUE CONVERTER STALL TEST

M1231103500122

This test measures the maximum engine speed when the 
selector lever is in the "D" or "R" position and the torque con-
verter stalls. This tests the operation of the torque converter 
(stator and one-way clutch operation) as well as the holding 
performance of the clutches and brakes in the transmission.

WARNING

Do not let anyone stand in front of or behind the vehi-
cle while this test is performed.

1. Check the transmission fluid level and temperature. Check 

the engine coolant temperature.

• Transmission fluid level: At the "HOT" mark on the dipstick

• Transmission fluid temperature: 70 − 80°C (158 − 176°F)

• Engine coolant temperature: 80 − 100°C (176 − 212°F)

NOTE: Measures transmission fluid temperature with scan 
tool MB991958 (MUT-III sub assembly).

2. Chock both front wheels.
3. Connect a tachometer.
4. Apply the parking and service brakes fully.
5. Start the engine.

CAUTION

• The throttle should not be fully open for any more than 

five seconds.

• If you repeat the stall test when the transmission fluid 

temperature is greater than 80

°C (176°F) move the 

selector lever to the "N" position and let the engine run 
at approximately 1,000 r/min for at least one minute. 
Wait until the transmission fluid temperature returns to 
80

°C (176°F) or less.

6. Move the selector lever to the "D" position. Fully depress the 

accelerator pedal and read the maximum engine speed.

Standard value: Stall speed: 2,300 

− 2,900 r/min

7. Move the selector lever to the "R" position. Fully depress the 

accelerator pedal and read the maximum engine speed.

Standard value: Stall speed: 2,300 

− 2,900 r/min

LOW-REVERSE 
BRAKE

UNDERDRIVE 
CLUTCH

ONE WAY CLUTCH

TORQUE 
CONVERTER

REVERSE 
CLUTCH

AC004018AB

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TORQUE CONVERTER STALL TEST JUDGMENT 
RESULTS

1. Stall speed is too high in both "D" and "R" ranges

• Malfunction of the torque converter (Slippage on the splines 

of the torque converter and the input shaft)

• Low line pressure

• Low-reverse brake slippage and malfunction of the one-way 

clutch

2. Stall speed is too high in "D" range only

• Underdrive clutch slippage

3. Stall speed is too high in "R" range only

• Reverse clutch slippage

• Low-reverse brake slippage

4. Stall speed is too low in both "D" and "R" ranges

• Malfunction of the torque converter (Slippage of the 

one-way clutch)

• Insufficient engine output

HYDRAULIC PRESSURE TESTS

M1231103800123

CAUTION

The transmission fluid temperature should be between 70 
− 80°C (158 − 176°F) during the test.
1. Check the transmission fluid level and temperature. Check 

engine coolant temperature.

• Transmission fluid level: "HOT" mark on the dipstick

• Transmission fluid temperature: 70 − 80°C (158 − 176°F)

• Engine coolant temperature: 80 − 100°C (176 − 212°F)

2. Raise the vehicle so that the wheels are free to turn.
3. Connect the special tools [3.0 MPa (427 psi) oil pressure 

gauge (MD998330) and adapters (MD998332, MD998900)] 
to each pressure discharge port.
NOTE: 

.

•

UC: Underdrive clutch pressure port

•

RC: Reverse clutch pressure port

•

OC: Overdrive clutch pressure port

•

LB: Low-reverse brake pressure port

•

2B: Second brake pressure port

•

TA: Torque converter apply pressure port

•

TR: Torque converter release pressure port

4. Restart the engine.
5. Check that there are no leaks around the special tool port 

adaptors.

6. Measure the hydraulic pressure at each port under the 

conditions given in the standard hydraulic pressure table, 
and check that the measured values are within the standard 
value ranges.

7. If the pressure is not within the standard value, stop the 

engine and refer to the hydraulic pressure test diagnosis 
table.

8. Remove the O-ring from the port plug and replace it.

AC101188AB

MD998900

MD998330

OIL PAN

AC101189AB

MD998900

MD998330

TRANSMISSION CONTROL 
CABLE

AUTOMATIC TRANSMISSION DIAGNOSIS

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9. Remove the special tool, and install the plugs to the 

hydraulic pressure ports.

10.Start the engine and check that there are no leaks around 

the plugs.

STANDARD HYDRAULIC PRESSURE TEST

NOTE: If the torque converter pressure is measured, the engine speed should be 1,500 r/min or less.

MEASUREMENT CONDITION

STANDARD HYDRAULIC PRESSURE MPa (psi)

TRANS-
MISSION 
RANGE

SHIFT 
POSITION

ENGINE 
SPEED 
(r/min)

UNDERDRIVE 
CLUTCH 
PRESSURE 
[UD]

REVERSE 
CLUTCH 
PRESSURE 
[RV]

OVERDRIVE 
CLUTCH 
PRESSURE 
[OD]

LOW- 
REVERSE 
BRAKE 
PRESSURE 
[LR]

SECOND 
BRAKE 
PRESSURE 
[2ND]

TORQUE 
CONVERTER 
PRESSURE 
[DR]

P

−

2,500

−

−

−

0.26 

− 0.36 

(38 

− 52)

−

0.22 

− 0.36 

(32 

− 52)

R

Reverse

2,500

−

1.27 

− 1.77 

(185 

− 256)

−

1.27 

− 1.77 

(185 

− 256)

−

0.50 

− 0.73 

(73 

− 106)

N

−

2,500

−

−

−

0.26 

− 0.36 

(38 

− 52)

−

0.22 

− 0.36 

(32 

− 52)

L

1st gear

2,500

0.98 

− 1.05 

(142 

− 152)

−

−

0.98 

− 1.05 

(142 

− 152)

−

0.50 

− 0.73 

(73 

− 106)

2

2nd gear

2,500

0.98 

− 1.05 

(142 

− 152)

−

−

−

0.98 

− 1.05 

(142 

− 152)

0.50 

− 0.73 

(73 

− 106)

3

3rd gear

2,500

0.78 

− 0.90 

(113 

− 131)

−

0.78 

− 0.90 

(113 

− 131)

−

−

0.45 

− 0.72 

(65 

− 104)

D

4th gear

2,500

−

−

0.78 

− 0.90 

(113 

− 131)

−

0.78 

− 0.88 

(113 

− 128)

0.45 

− 0.72 

(65 

− 104)

AUTOMATIC TRANSMISSION DIAGNOSIS

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HYDRAULIC PRESSURE TEST DIAGNOSIS TABLE

SYMPTOM

PROBABLE CAUSE

All hydraulic pressures are high.

Malfunction of the regulator valve

All hydraulic pressures are low.

Malfunction of the oil pump
Clogged internal oil filter
Clogged oil cooler
Malfunction of the regulator valve
Malfunction of the relief valve
Incorrect valve body installation
Improperly installed solenoid valves
Damaged solenoid valve O-rings

Hydraulic pressure is abnormal in 
reverse gear only.

Malfunction of the regulator valve
Clogged orifice
Incorrect valve body installation

Hydraulic pressure is abnormal in 3rd 
or 4th gear only.

Malfunction of the overdrive solenoid valve
Malfunction of the overdrive pressure control valve
Malfunction of the regulator valve
Malfunction of the switch valve
Clogged orifice
Incorrect valve body installation

Only underdrive clutch hydraulic 
pressure is abnormal.

Malfunction of the oil seal K
Malfunction of the oil seal L
Malfunction of the oil seal M
Malfunction of the oil seal Q
Malfunction of the underdrive solenoid valve
Malfunction of the underdrive pressure control valve
Malfunction of the check ball
Clogged orifice
Incorrect valve body installation

Only reverse clutch hydraulic 
pressure is abnormal.

Malfunction of the oil seal A
Malfunction of the oil seal B
Malfunction of the oil seal C
Clogged orifice
Incorrect valve body installation