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 B defective

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

3. Foreign material in separator plate orifice

4. 3rd accumulator defective

5. 4th accumulator defective

6. 3rd clutch defective

7. 4th clutch defective

Also check for:

- Check for a stored DTC, and check for loose connections.
- Test the solenoid valve function with the HDS.
- Inspect the A/T clutch pressure control solenoid valve body gasket, ATF feed pipes, and O-rings for wear and damage.
- 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 accumulator pistons, O-rings, and springs for wear and damage in the servo body.
- Inspect the mainshaft, secondary shaft, 3rd clutch, and 4th clutch for wear and damage.
- 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 inspect the clutch wave-plate height. If the discs and plates are worn or damaged, replace them as a set. If the wave-plate height is out of tolerance, replace the wave-plate. If they are OK, adjust the clearance with the clutch end-plate.
- Inspect the 3rd and 4th clutch feed pipes.
- If the 3rd clutch feed pipe is scored, replace it and the O-rings under the feed pipe flange.
- If the 4th clutch feed pipe is scored, replace it and the O-rings under the feed pipe flange.
- Replace the secondary shaft if the bushing for the 4th clutch feed pipe is loose or damaged.
- Replace the mainshaft if the bushing for the 3rd clutch feed pipe is loose or damaged.