Safeguard performance GM TH400 and 4L80-E vehicles on the street and track with reliable, high-strength servo upgrades from Sonnax  the leader in transmission innovation. New for fall 2021, Sonnax billet aluminum Low/Reverse servo pistons prevent failure at any power level, a critical safeguard when cast OE pistons are brittle and prone to breaking. Part No. 34914-01 fits all TH400 and 95-earlier 4L80-E; Part No. 34914-02 fits 96-later 4L80-E. Also new for TH400 and 95-earlier 4L80-E applications is an adjustable servo pin kit (Part No. 34912-01K) that gives builders easy access to five of the seven pin options discontinued by GM. The pin covers the five longest lengths for accurately setting Low/Reverse piston travel. It features an O-ring groove to prevent leakage of line pressure past the case pin bore. Visit www.sonnax.com for details on these and many more Sonnax upgrades.