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.
A vacuum test at the port indicated fails to hold at least 18 in-Hg.