Servo cover wears and direct clutch/servo release oil is lost, eventually resulting in direct clutch failure.
This servo piston cover with O-ring is designed to overcome piston wear and ensure hydraulic seal of direct clutch oil.
In vehicles with A727 ('71-later), 46RH/RE and 47RH/RE transmissions it is common to have long slide 2-3 shifts, direct (front) clutch failure or poor line pressure. These complaints can be caused by the front servo pin wearing the cover pin bore. In 3rd gear, direct clutch oil is present under the servo cover to release the band. Oil leaks due to a worn cover affect 2-3 shift and direct clutch durability. Sonnax front servo piston cover 22827-01 features an O-ring between the cover and pin to prevent wear and leakage.