September 30, 2005
Required tool kit F-56947J-TL63 is no longer in production. Check with your distributor for availability.
In Ford 5R55N units, as the valve bore wears at the inboard spool, converter clutch back pressure escalates with increased temperature and the back pressure valve does not stroke, preventing the TCC from applying fully. Wear at the outboard spool bore allows converter clutch pressure to exhaust, which reduces correct release pressure and allows the converter clutch to contact the cover prematurely. Sonnax oversized TCC back pressure valve kit 56947J-63K will restore proper hydraulic function and prevent future wear.
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.