Diesel Data: Automotive Repair

Excessive Shock or Engine Revs Up Abnormally High on 3-4 Upshift or 4-3 Downshift (A/T)




Excessive shock or engine revs up abnormally high on 3-4 upshift or 4-3 downshift

A/T clutch pressure control solenoid valve B defective

A/T clutch pressure control solenoid valve C defective

Foreign material in separator plate orifice

3rd accumulator defective

4th accumulator defective

3rd clutch defective

4th clutch defective

Notes

Check for a stored DTC, and check for loose connections.

Notes

Test the solenoid valve function with the HDS.

Notes

Inspect the A/T clutch pressure control solenoid valve body gasket, ATF feed pipes, and O-rings for wear and damage.

Notes

Check for a clogged orifice in the separator plate. If the orifice is clogged, remove it and clean the separator plate orifice.

Notes

Check the 3rd and 4th clutch pressures.

Notes

Inspect the 3rd and 4th accumulator pistons, O-rings, and springs for wear and damage in the servo body.

Notes

Inspect the mainshaft, secondary shaft, 3rd clutch, and 4th clutch for wear and damage.

Notes

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.

Notes

Inspect the 3rd and 4th clutch feed pipes.

Notes

If the 3rd clutch feed pipe is scored, replace it and the O-rings under the feed pipe flange.

Notes

If the 4th clutch feed pipe is scored, replace it and the O-rings under the feed pipe flange.

Notes

Replace the secondary shaft if the bushing for the 4th clutch feed pipe is loose or damaged.

Notes

Replace the mainshaft if the bushing for the 3rd clutch feed pipe is loose or damaged.