HIGH DEMAND ALERT: Shipping may be slightly delayed!
Thank you for making our Black Friday Sale such a huge success! Due to the overwhelming demand, some orders placed during the sale are still being processed. If your Black Friday order is pending, rest assured that it will be shipped soon.
For new orders, please note that slight shipping delays may still occur as our team continues working around the clock to fulfill all orders as quickly as possible. We deeply appreciate your patience and support during this busy time. Stock is moving fast, so don’t wait—shop now to secure your favorites!
Thank you for making our Black Friday Sale such a huge success! Due to the overwhelming demand, some orders placed during the sale are still being processed. If your Black Friday order is pending, rest assured that it will be shipped soon.
For new orders, please note that slight shipping delays may still occur as our team continues working around the clock to fulfill all orders as quickly as possible. We deeply appreciate your patience and support during this busy time. Stock is moving fast, so don’t wait—shop now to secure your favorites!
Speedmaster®
TH400 Extreme Duty Forward Drum & 300M Input Shaft 35-Spline
Overview
Take your GM TH400 transmission to the next level with this premium heavy duty forward drum and 300M input shaft combo. Engineered for high-power street, strip, or off-road use, this kit addresses the critical failure points of stock components with a focus on strength, precision, and reduced rotating mass.
Specs
| Brand: | Speedmaster |
| Part Number: | PCE623.1028.01 |
| Part Type: | Automatic Transmission Drum |
| Transmission Drum Material: | High-strength chromoly steel |
| Sprag Assembly Included: | No |
| Quantity: | Sold as a kit. |
Description
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.
Prop 65 Warning
This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.