Ford vehicles equipped with 5R55W and 5R55S transmissions frequently exhibit problems such as poor line rise, erratic line pressure, delayed engagement, no Reverse, poor shift quality and burnt clutches. These troubles can often be traced to wear in the OE boost sleeve, which allows pressure escape that causes driveability concerns. Installing Sonnax boost valve kit 56947J-74K eliminates pressure loss and revives line rise and shift quality in all ranges.
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.