R Ratio Servo Piston Kit

The Sonnax "R" Ratio Servo Piston Kit K36528R is a performance upgrade for Ford C6 automatic transmissions, specifically for mid-1968 and later models. It features a no-leak servo pin design that utilizes an O-ring and a PTFE ring. This innovative design effectively eliminates back pressure and leakage, allowing the servo piston to function correctly even in transmissions with worn case bores. The kit includes a cover, servo assembly, PTFE seal ring, O-rings, a gasket, and two selective return springs. The selective return springs allow for fine-tuning of shift quality to match driving preferences or specific performance requirements. Sonnax also offers a replacement seal kit (K36528R-SK) for this servo. Proper installation requires ensuring that the exhaust passage and both oil feed passages in the transmission case are unrestricted. Any previous modifications that blocked these passages must be removed for the servo to operate correctly.