September 30, 2005
Vehicles with Toyota/Lexus U760E and U760F transmissions may exhibit insufficient line rise in Reverse, delayed or slipping Reverse, and/or burned C3, B1, and B4 clutches. Continuous oscillation of OE steel boost valve within aluminum boost sleeve causes premature wear, creating a path for boost pressure to exhaust. Installing improved material Sonnax Reverse boost valve kit 47740-38K restores the hydraulic integrity of the boost circuit to recover normal Reverse operation.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.