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:

- Test the solenoid valve function with the HDS.
- Inspect the A/T clutch pressure control solenoid valve body gasket, the ATF feed pipes, and the 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 ATF strainer for debris. If the strainer is clogged with particles of steel or aluminum, inspect the ATF pump. If the ATF pump is OK, find the damaged components that caused the debris. If no cause for contamination is found, replace the torque converter.
- Inspect the 3rd and 4th accumulator pistons, the O-rings, and the springs for wear and damage in the servo body.
- Check the 3rd and 4th clutch pressures. A/T Pressure Test
- Inspect the mainshaft, the secondary shaft, the 3rd clutch, and the 4th clutch for wear and damage.
- Inspect the clutch piston, the clutch piston check valve, and the 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 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 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.