January 14, 2014
ZF6HP21/28/34 (Generation 2) transmissions are equipped with an aluminum sleeve for the clutch A and E control boost valve. This material is prone to wear from valve plunger reciprocation. Failure of this sleeve results in a variety of shift problems and solenoid codes. The Sonnax clutch A and E control boost valve kit 95740-28K will restore the correct hydraulic clearance and proper function of the assembly.
Kit is NOT compatible with ZF6HP19/26/32 (Gen.1) units. To differentiate between Gen. 1 and Gen. 2 valve bodies, see ZF Identification Guide.
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.