NO.24 SHIFT CONCERN: HARSH 3-4 SHIFT [LA4AX-EL (CD4E)]


id0503a2805700

24

Shift concern: harsh 3-4 shift

POSSIBLE CAUSE

• Powertrain control system malfunction
• Control valve body malfunction
• Oil pump malfunction
2/4 band and servo component malfunction
• Coasting clutch component malfunction
• Direct clutch component malfunction
• Transaxle case malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
Powertrain control system
• Are there any malfunctions with the following?
- Electrical input/output
- Vehicle wiring harness
- PCM
- Electrical pressure control (EPC) solenoid
- Transaxle range (TR) switch
- Vehicle speedometer sensor (VSS)
- 3-2 timing/coasting clutch solenoid (3-2T/CCS)
- Transaxle fluid temperature (TFT) sensor
- Turbine shaft speed (TSS) sensor
- Throttle position (TP) sensor
- Mass air flow (MAF) sensor
- TCC solenoid
Yes
Perform OBD test
Perform DTC troubleshooting
No
Go to the next step
2
Control valve body
• Do any of the following malfunctions exist?
- Bolts are not tightened to the specification
- Gasket leaks
- Line modulator valve (also harsh 1-2 and 2-3 shifts), 3-2 control valve, 2/4 accumulator valve, coasting clutch valve are stuck, damaged, or misassembled
- Hydraulic passages are damaged
- Separator plates are damaged or blocked
Yes
Service if necessary
No
Go to the next step
3
Oil pump
• Do any of the following malfunctions exist?
- Bolts are not tightened to the specification
- Gasket is damaged
- Porosity/cross leakage
- Coasting clutch Teflon seals are damaged
Yes
Service if necessary
No
Go to the next step
4
2/4 band and servo component
• Do any of the following malfunctions exist?
- 2/4 band and/or reverse clutch drum component are damaged, worn, or misassembled
- Servo piston or cover is damaged or leaking
- Springs are damaged
Yes
Service if necessary
No
Go to the next step
5
Coasting clutch component
• Do any of the following malfunctions exist?
- Piston or seals are damaged or missing
- Friction is damaged or worn
- Inspect the ball for not functioning
Yes
Service if necessary
No
Go to the next step
6
Direct clutch component
• Do any of the following malfunctions exist?
- Piston or seals are damaged or missing
- Inspect the ball for damage, missing, or leaking
- Return spring is damaged
- Friction elements are damaged
- F/C/D clutch cylinder splines are damaged
Yes
Service if necessary
No
Go to the next step
7
Transaxle Case
• Is the band anchor damaged?
Yes
Service if necessary
No
The malfunction is not in the automatic transaxle
Go to the engine symptom troubleshooting
8
• Verify the test results.
- If normal, return to the diagnostic index to service any additional symptoms.
- If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.
• If the vehicle is repaired, troubleshooting is completed.
• If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM.