TH400, 3L80

For use with turbine support bushing in converter.

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.

This Sonnax extreme duty input shaft is ideal for any high-horsepower racing application. It has a 1-1/8" diameter, 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. Its forward drum spline is designed to be used with aftermarket drums with compatible 28-tooth spline, including Sonnax heavy duty forward drum (part # 36903) and Smart-Tech® drum module (36913K).

• Extreme duty, 1-1/8" dia., 35-spline input shaft is 35% stronger than standard 1" shafts
• High-strength 300M steel shaft undergoes additional processing to build in resistance to fracture
• Ideal for any high-horsepower racing application

Note: Using this shaft requires changing to a 35-spline turbine hub in the torque converter and use of pump cover big shaft stator support tube kit with larger inner diameter.

Specifications:

• Shaft Material: 300M
• Shaft Dia.: 1.125"
• Front Spline Tooth Count: 35

36902ES Instruction Sheet

Sonnax Extreme Duty Input Shaft - 35280-02