Worn OE boost sleeve allows critical pressure loss that prevents proper Reverse operation.
Stop boost leakage and renew Reverse performance by installing Sonnax boost valve kit.
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.