Transmission Oil Pan Gasket GM TH400

The Transmission Oil Pan Gasket GM TH400 by Mr. Gasket is a precision rubber and nylon sealing component engineered for Turbo 400 automatic transmissions. This gasket prevents fluid leakage at the transmission pan interface—a critical seal that stops ATF from escaping under pressure and heat cycling. Mechanics and performance builders rely on quality pan gaskets to maintain transmission fluid levels and prevent costly internal damage from starvation or contamination.

Constructed from durable rubber and nylon composite materials, this gasket withstands the thermal expansion and contraction cycles inherent to transmission operation, particularly in high-performance or heavy-duty applications where fluid temperatures regularly exceed 200°F. The TH400 transmission demands a gasket that seals reliably across the pan flange without degradation from friction modifier additives or synthetic ATF formulations. Mr. Gasket's design ensures a compression fit that maintains seal integrity across repeated pan removal and reinstallation cycles, critical for builders who regularly access the transmission for servicing or tuning.

This gasket is essential for any TH400 rebuild, restoration, or pan service where original equipment seals have hardened, shrunk, or failed. Hot rod builders, drag racing enthusiasts, and street performance mechanics depend on reliable pan gaskets to eliminate weeping leaks before final assembly and dyno testing. The Transmission Oil Pan Gasket GM TH400 fits all standard TH400 transmission pans and integrates seamlessly with both stock and modified cooling systems. Proper installation requires pan cleaning, torque-to-spec fastening, and fluid inspection post-installation to confirm seal effectiveness and fluid integrity.