4L85-E Archives - Transmission Digest
GM 4L80/85-E Extreme Duty Input Shaft

Input shaft failure is common in performance GM 4L80-E and 4L85-E units running with extreme horsepower. OE and aftermarket shafts simply don’t hold up in these conditions, leading to spline twist and shaft breakage. Recommended for applications above 1,000-hp, the Sonnax extreme duty input shaft (p/n 34670-02) is manufactured from high-strength Aermet steel alloy with

GM 4L80/85-E 2-3 Accumulator Spring

This new Sonnax 2-3 accumulator spring (p/n 34931-01) for GM 4L80/85-E units is a direct replacement spring that has been stress relieved and shot-peened for increased durability compared to factory springs.