November 14, 2016
Ford vehicles with 4R70E, 4R70W, 4R75E, 4R75W and AODE transmissions may exhibit insufficient line rise in Reverse, delayed or slipping Reverse, and/or a burnt Reverse clutch. Continuous oscillation of the OE boost valve within the boost sleeve causes premature wear, creating a path for boost pressure to exhaust and causing these concerns. Installing Sonnax boost valve kit 76948-02K eliminates pressure loss, restoring proper line rise and robust Reverse action.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.