Sonnax TH400 Turbo 400 HD Servo Piston

Precision heavy-duty servo piston for the GM TH400 Turbo 400 3L80 heavy-duty automatic transmission. This Sonnax component features oversized apply area engineered for the TH400's demanding operating environment. Proper servo function is essential for firm band application and reliable shift engagement under high-torque conditions.

Direct replacement for all 1964-1990 TH400 applications in Chevrolet, GMC, Pontiac, Buick, and Oldsmobile vehicles. Whether rebuilding a daily driver or a drag car, this servo component ensures consistent performance every time.