Sonnax GM 6L80/6L90 4-5-6 Clutch Apply Piston Kits

Never Miss a Shift for Fourth, Fifth, and Sixth Gear

Correct OE design flaws in GM 6L80 and 6L90 six-speed automatic transmissions with Sonnax Clutch Apply Piston Kit. The original design uses an insufficient piston to plate apply surface area while the backing plate flexes, resulting in premature clutch failure.  Sonnax fixed the problem by modifying an OE piston dam and clutch apply piston for a specific Sonnax designed piston apply ring along with a rigid backing plate