GM 700-R4 4L60 & 4L60E Super Servo 4th Apply Piston & Cover This Super Servo 4th Apply Piston & Cover from Superior will improve all 700-R4, 4L60 & 4L60E Transmissions. This Super Servo will provide better holding capacity in 4th gear, has an improved lip seal design on pistol which will provide less leakage, eliminates the drag from 4-3 release and is constructed of billet aluminum.