Input shaft failure is a common problem in GM TH400 transmissions running with added horsepower. Sonnax notes that it offers heavy and extreme duty input shafts compatible with heavy duty forward drum part no. 34554-01 and Smart-Tech drum module no. 34555-01K.
Part numbers include:
• Heavy Duty Input Shaft 30280-01
• Heavy Duty Input Shaft 30280-02
• Extreme duty Input Shaft 35280-02
• Extreme Duty Input Shaft 27280-02