300M Alloy Main Shaft w/ Rolled Splines

300M ALLOY MAIN SHAFT w/ROLLED SPLINES (ALSO FITS 4L80E)

The Coan Racing COA‑22811 300M Alloy Main Shaft with Rolled Splines is a race-grade powerhouse designed for both the TH400 and 4L80E transmissions. Crafted in the USA from high strength 300M alloy, this main shaft is engineered to withstand brutal torque loads while offering superior durability. The rolled spline design ensures a cleaner, more precise spline profile that minimizes stress concentrations and significantly reduces the risk of fatigue or failure under high-power conditions.

This shaft is built for no-nonsense performance upgrades, dropping directly into TH400 and 4L80E cases without need for modifications, making it a seamless replacement for OEM shafts. Whether you're building a bracket drag car or outfitting a heavy-hauler, the 300M alloy construction, combined with precision-rolled splines, results in a more reliable drivetrain that stays locked under pressure and performs consistently over many cycles.

In short, the COA‑22811 is a must-have for high stress rebuilds and performance builds that demand proven strength, bore resistance, and drivetrain dependability.