The B2 clutch in Mercedes 722.9 transmissions is applied in first through fourth gears, and the BR clutch is used during Reverse operation. The B2/BR regulator valve controls the apply rate for these clutches. Bore wear at the B2/BR regulator valve allows pressure loss that affects clutch apply timing, resulting in harsh engagement, delayed Forward and Reverse, flares, and harsh 4-5 shifts. Reconditioning the bore and installing Sonnax oversized B2/BR regulator valve kit 88740-04K renews critical clearances to restore normal Forward and Reverse operation.
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.