GM 700-R4 Up-Shift Full Throttle Boost Valve Plunger Sleeve This Up-Shift Full Throttle Boost Valve Plunger Sleeve from Superior will improve all 700-R4 Transmissions from 1981-1993. This sleeve allows full throttle 3-4 up-shifts and the 4-3 detent will become less sensitive at part throttle. The 700-R4 Up-Shift Sleeve can be installed without removing the valve body from the case.