Th400 Transkit

The TH400 Transkit from B and M AUTOMOTIVE is a professional-grade transmission rebuild and modification kit designed for serious enthusiasts and mechanics upgrading or restoring Turbo 400 automatic transmissions. Whether you're building a high-performance street machine, drag racing platform, or restoring a classic American muscle car, this transkit provides the critical internal components needed to transform a tired factory transmission into a reliable, responsive power plant. The TH400's legendary durability makes it a preferred platform for both stock restorations and radical modifications, and this kit addresses the most common wear points and upgrade requirements.

This transkit contains precision-engineered internal components that enhance shift quality, durability, and torque capacity. The kit tackles stock weaknesses through improved clutch packs, updated seals, and optimized friction materials that reduce slippage and heat generation under load. At 11.63 lbs, the packaged kit includes all necessary gaskets, seals, and internal hardware required for a complete teardown rebuild or selective upgrade installation. The compact dimensions (16.5 x 5.7 x 18.7 inches) contain multiple components organized for efficient shop workflow, allowing mechanics to access individual elements without excessive handling or risk of misplacement during assembly.

Professional transmission rebuilders, weekend warriors, and restoration shops benefit most from this kit when addressing TH400 units experiencing slipping, delayed engagement, or soft shifts. Installation requires transmission removal and full disassembly—not a job for first-timers, but entirely manageable for experienced mechanics with proper tools and service documentation. This transkit is compatible with TH400 transmissions installed in Chevrolet, Pontiac, Oldsmobile, and Buick platforms from the 1960s through 1980s, as well as retrofit applications in hot rods and custom builds. The B and M AUTOMOTIVE part number 20229 (UPC 019695202293) ensures correct fitment and quality assurance for your specific application.