GM 4L80E Transmission Superior Shift Correction Kit This Shift Correction Kit from Superior will improve all 4L80E Transmissions from 1991-2005 This Shift Correction Kit helps eliminate the following problems: Runaway high pressure, erratic pressure rise, converter shudder, falls out of 4th gear, inconsistent shift feel, premature unit failure and shift solenoid filter blow-out. This Shift Correction Kit will come with installation directions in English, illustrations and the drill bits that the installation will require (Note: Not all drill bits are included).