The K3 clutch in Mercedes 722.9 transmissions is applied in all gears except fourth and is controlled by the K3 shift valve. Oscillation of this valve in its bore causes excess wear in the aluminum casting, which allows crucial shift signal fluid to leak to exhaust. This can result in burnt K3 clutches, delayed or harsh engagement, 4-5 issues or loss of Forward and Reverse operation. Reconditioning the bore and installing Sonnax oversized K3 shift valve kit 88740-06K eliminates this wear for restored hydraulic integrity and K3 control 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.