Input shaft failure is a common problem in performance GM TH400 transmissions running with extreme horsepower. OE and aftermarket shafts simply don’t hold up in these conditions, leading to spline twist and shaft breakage.
Sonnax extreme duty input shaft 35280-02 is ideal for any high horsepower racing application. It has a 1 1/8" dia., the largest size that fits within a stock style stator tube. Manufactured from 300M high-strength steel with additional processing for resistance to fracture, this shaft strikes the perfect balance between strength and ease of installation.
It is intended to be used with aftermarket converters with internal turbine support, and its Forward drum spline is designed to be used with heavy duty forward drum 34554-01 or other aftermarket drums with compatible 28-tooth spline.
Using this shaft requires changing to a 35-spline turbine hub in the torque converter and use of pump cover big shaft stator tube kit 28154S-125 with larger inner diameter.