Excessive Shock or Flares on 3-4 Upshift or 4-3 Downshift

Excessive shock or flares on 3-4 upshift or 4-3 downshift

Diagnostic Procedure:

1. A/T clutch pressure control solenoid valve A defective

2. A/T clutch pressure control solenoid valve B defective

3. A/T clutch pressure control solenoid valve C defective

4. 4th clutch transmission fluid pressure switch defective

5. Shift fork shaft stuck

6. Foreign material in separator plate orifice

7. Servo control valve defective

8. 3rd accumulator defective

9. 4th accumulator defective

10. 3rd clutch defective

11. 4th clutch defective

12. Clutch end plate clearance incorrect

Also check for:

- Check for a stored DTC, and check for loose connectors.
- Inspect the O-rings, and check the shift solenoid valve for seizure.
- Inspect the A/T clutch pressure control solenoid valve body gasket and ATF feed pipes for wear and damage. If the A/T clutch pressure control solenoid valve is stuck, inspect the CPC valves.
- Check for clogged orifice in the transmission fluid pressure switch connector. If the orifice is clogged, remove it and clean the connector.
- Check the 3rd and 4th clutch pressures.
- Inspect the clutch piston, clutch piston check valve, and O-rings. Check the spring retainer for wear and damage. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and plates for wear and damage, and also inspect the clutch wave-plate height. If the discs and plates are worn or damaged, replace the discs and plates as a set. If the wave-plate height is out of tolerance, replace the wave-plate. If the discs and plates are OK, adjust the clearance with the clutch end plate.