TH400 Extreme Duty Forward Drum & 300M Input Shaft 35-Spline

Heavy Duty Forward Drum

• Constructed from high-strength chromoly steel – providing exceptional durability without the weaknesses of cast iron or aluminum.
• Lightweight design – 3 lbs lighter than stock and nearly the same weight as an aluminum drum, without compromising strength.
• Oversized 28-tooth shaft-to-drum spline – significantly stronger than the factory design, addressing a common failure point.
• Enhanced clutch engagement – features dual clutch splines (28 vs. 14) for better support of clutch separators.
• Precision-machined lightening holes – reduce rotating mass and align with input speed sensors in aftermarket cases.
• Optimized design – includes ribbing and internal diameter reduction at the middle seal area for further weight savings.
• High-RPM checkball capsule included – prevents pressure drop at 5500+ RPM for consistent clutch performance.
• No middle seal required – compatible with clutch volume spacer kits if fill/drain time needs adjustment.
  

300M Extreme Duty Input Shaft

• Made from ultra-tough 300M steel – heat-treated for exceptional resistance to twist and fracture under extreme torque.
• 1-1/8" diameter, 35-spline design – the strongest configuration that fits within a stock-style stator tube.
• 35% stronger than standard 1" shafts – built for serious racing and high-horsepower abuse.
• Compatible with aftermarket drums using 28-tooth internal spline – ensures secure engagement with heavy duty drum.
  

Installation Notes:

• Input shaft requires a 35-spline turbine hub in the torque converter.
• Must be used with a large-diameter stator support tube.