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. Servo control valve defective

7. Foreign material in separator plate orifice

8. 3rd accumulator defective

9. 4th accumulator defective

10. 3rd clutch defective

11. 4th clutch defective

12. Clearance between the clutch end-plate and the top disc is incorrect

Also check for:

- Check for a stored DTC, and check for loose connections.
- Inspect A/T clutch pressure control solenoid valve with the HDS.
- Inspect A/T clutch pressure control solenoid valve body gasket, ATF feed pipes, and O-rings for wear and damage.
- Check for a missing shift fork bolt on the shift fork shaft.
- Check the shift fork shaft detent for wear and damage.
- Check for a stuck servo valve in the regulator valve body, and check the O-ring for wear and damage.
- Check the servo control valve in the main valve body for free movement, and check the valve spring for wear and damage.
- Check for a clogged orifice in the transmission fluid pressure switch connector. If the orifice is clogged, remove it and clean the connector.
- Check for a clogged orifice in the separator plate. If the orifice is clogged, remove it and clean the separator plate orifice.
- Check the 3rd and 4th clutch pressures.
- Inspect the 3rd and 4th clutches for wear and damage.
- Inspect the clutch piston, the clutch piston check valve, and the O-rings. Check the spring retainer for wear, damage, and peeling. Inspect the clearance between the clutch end-plate and the top disc. If the clearance is out of tolerance, inspect the clutch discs and the plates for wear and damage, and inspect the clutch wave-plate height. If the discs and the plates are worn or damaged, replace them as a set. If the wave-plate height is out of the tolerance, replace the wave-plate. If they are OK, adjust the clearance with the clutch end-plate.
- Check the 3rd and 4th accumulator pistons, O-rings, and springs in the accumulator body for wear and damage.