NO.1 NO FORWARD ENGAGEMENT ONLY [LA4AX-EL (CD4E)]

id0503a2803600

1

No forward engagement only

POSSIBLE CAUSE

• Internal or external shift linkage malfunction
• Oil pump malfunction
• Control valve body malfunction
• Forward clutch and coasting clutch component malfunction
• Low one-way clutch component malfunction
• Forward one-way clutch component malfunction
• Low intermediate carrier component malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
Internal or external shift linkages
• Do any of the following malfunctions exist?
- Damage
- Misadjustment
- Misassembly
(See SELECTOR LEVER REMOVAL/INSTALLATION.)
Yes
Service if necessary
No
Go to the next step
2
Control valve body
• Do any of the following malfunctions exist?
- Bolts are not tightened to the specification
- Gaskets are damaged, or leaking
- Pressure tap plate/Gasket are leaking or damaged
- Separator plates are damaged
- Hydraulic passages are damaged
- Main regulator valve is stuck, damaged, or misassembled
- Forward accumulator is leaking
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
- Gaskets are damaged
- Porosity/cross leaks and/or the ball plug is missing, leaking, or the hole is plugged
- Oil pump support seal rings, #3 and #4 are damaged
Yes
Service if necessary
No
Go to the next step
4
Forward clutch and coasting clutch component
• Do any of the following malfunctions exist?
- Seals or pistons damaged
- Return spring is damaged
- Ball check valve is damaged
- Friction elements are severely damaged or worn
- Forward/coasting/direct (F/C/D) clutch cylinders are damaged, leaking, misassembled, or stuck
- Welding between cylinder and hub is broken, or splines are damaged
Yes
Service if necessary
No
Go to the next step
5
Low one-way clutch component
• Do any of the following malfunctions exist?
- Wear
- Damage
- Misassembly
Yes
Service if necessary
No
Go to the next step
6
Forward one-way clutch component
• Do any of the following malfunctions exist?
- Wear
- Damage
- Misassembly
Yes
Service if necessary
No
Go to the next step
7
Low intermediate carrier
• Do any of the following malfunctions exist?
- Damage
- Misassembly
Yes
Service if necessary
No
The problem is resolved
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.