Sonnax 4L60E 4L65E 4L70E Transmission Sure Cure Kit Sonnax Performance Pack HP-4L60E-01 combines innovative heavy duty/performance calibration for firmer shifts under load without sacrificing low-speed drivability. The precision components in this kit upgrade the 4L60-E for maximum performance and durability by recalibrating pressures, re-calibrating shift accumulation and including improved parts for areas that commonly wear. This kit is suitable for any heavy duty application and is a critical foundation for other upgrades when modifying the 4L60-E for high performance use. · Shorter shifts which get progressively firmer with load · Faster pressure increase and higher overall pressure for greater clutch/band holding power · Three ultra-reliable, patented, billet pinless accumulator pistons · Unique 1-2 accumulator spring combination for shifts with character · Improved high RPM pressure · Third accumulator valve gets the 2-3 right the first time, every time · Consistent results, no guessing on calibration · Prevents worn accumulators and separator plate · Optional TCC on-off conversion prevents excess TCC pressure