GM 4L65E & 4L70E Reverse Boost Valve and Sleeve This Reverse Boost Valve and Sleeve Kit from Superior will improve all 4L65E and 4L70E Transmissions from 2005-Up. This Problem Solver replaces the worn out O.E. aluminum valves and is made of hardened steel to resist wear. The boost valve replaces the 1.804" stock sleeve for higher capacity and assured tolerance at bore mating surface.