Sonnax adjustable rear servo pin kit 34912-01K replaces GM TH400 and '95-earlier 4L80-E servo pins. OE pins have seven different lengths to allow for adjustment of the Low/Reverse band but are no longer available from GM. The Sonnax pin kit has an adjustment range that covers the five longest OE pins to allow for accurate setting of the Low/Reverse servo piston travel. The pin features an O-ring groove to prevent leakage of line pressure past the case pin bore.