4L60E 1-2 SHIFT Enhanced Performance ACCUMULATOR SPRING BY SONNAX  200-4R, 4L60, 4L60-E, 4L65-E, 4L70-E Sonnax enhanced performance accumulator spring provides firmer 1-2 shifts for the enthusiast that appreciates quick, positive shift feel in listed GM units. The Sonnax spring design provides a performance shift feel but does not reduce accumulator piston travel. This allows for a firmer – but still cushioned – shift that minimizes shock to the band and shafts. The Sonnax spring achieves the same effect as the common shop practice of replacing the OE 1-2 accumulator spring with the THM 350 direct accumulator piston spring. The Sonnax spring also may be used as a replacement for the THM 350 direct accumulator piston spring. Note : In ‘95-later units, install with the spring against the housing. HEAVY DUTY (FIRMER) SHIFTS / BETTER BAND APPLICATION   ALSO SOLD IN STORE WITH WIDE ALTO BAND