Master Overhaul Kit Th40

The B and M AUTOMOTIVE Master Overhaul Kit TH40 is a complete transmission rebuild kit engineered for TH400 automatic transmissions. This master kit delivers all the critical internal components required for a full overhaul, including precision clutches, bands, filter, gaskets, and seals. Whether rebuilding a stock transmission or preparing one for performance use, this kit consolidates the essential wear items into a single, organized package, eliminating the need to source components individually.

The TH400 is legendary for its strength and longevity, but like any automatic transmission with hundreds of thousands of miles, internal friction materials and seals degrade over time. This master overhaul kit replaces those wear surfaces with fresh OEM-spec clutches and bands, restoring shift quality and eliminating slippage. The inclusion of OEM gaskets and seals ensures proper fluid containment and prevents post-rebuild leaks—a common pitfall when mixing old and new internals. At 11.65 lbs, the kit is compact enough to handle during bench work while containing everything needed for a professional-quality rebuild.

This rebuild kit is designed for mechanics and enthusiasts tackling a TH400 transmission overhaul on muscle cars, trucks, and performance vehicles. The TH400 transmission rebuild process benefits greatly from using a matched master kit rather than piecing together components, as it ensures compatibility and reduces assembly errors. Ideal for anyone restoring a classic muscle car, refreshing a truck's drivetrain, or preparing a transmission for increased power, this kit delivers the core components necessary to return the transmission to like-new condition.