Toyota/Lexus vehicles with A750, A760, A960 and AB60 series transmissions may exhibit insufficient line rise in drive ranges and excessively high pressures in Reverse. This may be caused by continuous oscillation of the steel boost valves within the cast aluminum sleeve, creating excessive wear and a path for EPC, cutback and Reverse pressure to leak.
Severe wear at the reverse circuit allows line pressure to cross leak to the EPC circuit, causing abnormally high pressures. Wear in the cutback circuit allows fluid to cross leak into an exhaust circuit, causing low line pressure resulting in soft shifts and band failures. The Sonnax boost valve kit 147741-01K has upgraded materials and minimal clearances to prevent wear and restore proper hydraulic control.
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.
January 16, 2014
September 30, 2005
Either a wet air test (WAT) or a vacuum test at the locations shown result