Mitsubishi Montero Sport (2004+). Manual - part 699

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-361

STEP 3. Check when shift shock occurs.
Q: When does the shift shock occur?

When engaging from "N" to "D" and "N" to "R" : Go to 

Step 4.

When the vehicle starts moving : Go to Step 5.

STEP 4. Replace the transmission oil pump.
(1) Remove the transmission.

(2) Replace the transmission oil pump. (Oil pump cannot be 

repaired). Refer to GROUP 23B, Transmission 

P.23B-19

. 

Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 6.

STEP 5. Disassemble and clean the valve body.

Check the installation bolts for looseness and the O-ring, 
valves and valve body for damage. Repair or replace the faulty 
parts. Refer to GROUP 23B, Valve Body 

P.23B-67

.

Replace the valve body assembly if the damages are thought 
to be irreparable. Then check the symptom.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 6.

STEP 6. Replace the PCM.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Start over at Step 1.

AC103774

OIL PUMP

AF

AC004272

VALVE BODY ASSEMBLY

AB

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-362

INSPECTION PROCEDURE 9: Shift Shock and Slipping

.

COMMENT
If shift shock when driving is due to upshifting or 
downshifting and the transmission speed become 
higher than the engine speed, the cause is probably 
abnormal line pressure or a malfunction of a solenoid 
valve, transmission oil pump, valve body or of a 
brake or clutch.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this case:)

• Abnormal line pressure

• Malfunction of each solenoid valve

• Malfunction of the transmission oil pump

• Malfunction of the valve body

• Malfunction of each brake or each clutch

• Malfunction of the PCM

DIAGNOSIS

Required Special Tool:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

STEP 1. Using scan tool MB991958, check actuator test.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958. 
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to actuator test mode for following 

items.

a. Item 01: Low-reverse solenoid valve
b. Item 02: Underdrive solenoid valve

c. Item 03: Second solenoid valve

d. Item 04: Overdrive solenoid valve

• An audible clicking or buzzing should be heard when 

the solenoid valves are energized.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are the solenoid valves operating properly?

YES : Go to Step 2.
NO :  Repair or replace the solenoid valves. Refer to 

GROUP 23B, Valve Body 

P.23B-67

. Then confirm 

that the symptom is eliminated.

AK303629AB

MB991911

MB991827

MB991824 

16-PIN

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-363

STEP 2. Check the hydraulic pressure.

(1) Measure the hydraulic pressure of each element. Check if 

each hydraulic pressure is within the standard value. Refer 
to 

P.23A-26

, Hydraulic Pressure Test.

(2) If some elements pressure are within the standard value 

and some are not, recheck the symptom.

Q: Are all hydraulic pressures within the standard value?

YES : Go to Step 6.
NO :  Go to Step 3.

STEP 3. Adjust the line pressure.

Adjust the line pressure. Refer to 

P.23A-39

, Line Pressure 

Adjustment. Then check the symptom.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 4.

STEP 4. Replace the transmission oil pump.
(1) Remove the transmission.

(2) Replace the transmission oil pump. (Oil pump can not be 

repaired). Refer to GROUP 23B, Transmission 

P.23B-19

. 

Then check the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 5.

STEP 5. Disassemble and clean the valve body.

Check the O-ring installation bolts for looseness and the valve 
body for damage. Repair or replace the faulty parts. Refer to 
GROUP 23B, Valve Body 

P.23B-67

.

Replace the valve body assembly if the damages are thought 
to be irreparable. Then check the symptom.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 7.

AC103774

OIL PUMP

AF

AC004272

VALVE BODY ASSEMBLY

AB

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-364

STEP 6. Check each brake and clutch.

(1) Remove the transmission.
(2) Check the facing for seizure and piston seal ring for 

damage and interference with retainer. Repair or replace 
the faulty parts. Refer to GROUP 23B, Transmission 

P.23B-19

, Underdrive Clutch 

P.23B-63

, Reverse and 

Overdrive Clutches 

P.23B-54

. Then check for the symptom.

Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Go to Step 7.

STEP 7. Replace the PCM.
Q: Is the symptom eliminated?

YES : The procedure is complete.
NO :  Start over at Step 1.

INSPECTION PROCEDURE 10: Early or Late Shifting All Gears

.

COMMENT
If all shift points are early or late while driving, the 
cause is probably a malfunction of the output shaft 
speed sensor, TP sensor or a solenoid valve.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this case:)

• Malfunction of the output shaft speed sensor

• Malfunction of the TP sensor

• Malfunction of each solenoid valve

• Abnormal line pressure

• Malfunction of the valve body

• Malfunction of the PCM

DIAGNOSIS

Required Special Tool:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

AC103774

REVERSE
CLUTCH

SECOND BRAKE

LOW-REVERSE
BRAKE

UNDERDRIVE
CLUTCH

AJ

OVERDRIVE CLUTCH