Automatic Transmission model 6T40 applicable for Buick, Chevrolet, GMC, and etc. 6T40 automatic transmission piston seal kit consisted with 5 different types of bonded piston seals that apply in different parts within the automatic transmission, provides transmission system with excellent sealing performace.  WinTek's bonded piston seals use VAMAC as our material of choice when producing. VAMAC's superior material characteristics can withinstand high pressure, resist heat, oil, and hydraulic fluids, and reduce of friction rate.