Cause:
Breakage of the 4-3 pre-stroke valve spring prevents proper valve function.
Correction:
Replace with the reduced-stress Sonnax spring.
Complaints of no 4th or 5th gear, codes 734 and/or 735, and solenoid C codes can occur on the 5R55N due to a broken 4-3 pre-stroke valve spring. The 4-3 pre-stroke valve controls the apply and release rate of the intermediate servo and direct clutch, which should be applied in 4th and 5th gear. The Sonnax 4-3 Pre-Stroke Valve Spring addresses these complaints. This spring is not used on 5R55W & S units.
Spring is made from chrome-silicon alloy, which allows higher working stresses than typical music wire spring material.
Spring configuration reduces operating stresses at the critical regulating positions of the valve by 8%.
Symptoms:
Cause: Breakage of the 4-3 pre-stroke valve spring prevents proper valve function.
Correction: Replace with the reduced-stress Sonnax spring.
Complaints of no 4th or 5th gear, codes 734 and/or 735, and solenoid C codes can occur on the 5R55N due to a broken 4-3 pre-stroke valve spring. The 4-3 pre-stroke valve controls the apply and release rate of the intermediate servo and direct clutch, which should be applied in 4th and 5th gear. The Sonnax 4-3 Pre-Stroke Valve Spring addresses these complaints. This spring is not used on 5R55W & S units.
SONNAX Installation Instructions