Wear can occur in Gen. 1 and Gen. 2 Ford 6F35 clutch control valve bores. This wear allows critical clutch apply pressure and oil loss which can cause shifting issues and a burnt clutch. Reconditioning the bore and installing Sonnax oversized low reverse/overdrive (4-5-6) clutch regulator valve kit 144740-43K restores correct pressure regulation.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.