It is critical that the lip of the piston seal in the 6T70 transaxle not be damaged as the seal is installed into the piston bore. Any nicks or cuts will affect clutch apply pressure and transaxle function. GM-46628 is a two piece tool that includes a protector, to allow the low-reverse piston seal lip to slide smoothly over any retaining ring grooves, and a pusher to evenly push on the piston in the narrow clearance space between the piston and case, until it reaches the correct position.