Sonnax enhanced performance accumulator spring 77704S provides firmer 1-2 shifts for the enthusiast that appreciates quick, positive shift feel in listed GM units. The Sonnax spring design provides 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.