Transmission Pan GM Tur bo 400 Finned with Gaske

The Transmission Pan GM Turbo 400 Finned with Gasket from Specialty Products Company (Part Number 8593BK) is a purpose-built aluminum replacement pan engineered for TH400 automatic transmissions commonly found in marine powerboats, diesel trucks, and high-performance applications. The finned design significantly increases surface area for improved heat dissipation, a critical factor in marine environments where transmission fluid temperatures can climb rapidly under sustained throttle or towing loads.

This transmission pan replaces the stock sump with aluminum construction that runs cooler and lighter than OEM steel. The finned geometry acts as a passive cooling system, radiating excess heat directly into the surrounding air or water spray—especially valuable in saltwater environments where corrosion and thermal stress accelerate wear on transmission components. Black paint provides both corrosion protection and a professional finished appearance. The integrated gasket surface ensures a secure seal when installed with an appropriate transmission fluid gasket, preventing leaks that can lead to catastrophic transmission failure. Weighing 6.01 pounds and measuring 13.75 × 17.65 inches, it fits within standard TH400 mounting points without modification.

Buyers upgrading transmission cooling systems—whether for offshore fishing boats running hard all day, diesel pickups towing heavy loads, or street/strip performance builds—benefit from lower fluid temps and extended transmission life. This pan works as part of a comprehensive cooling strategy alongside external coolers and quality synthetic ATF. TH400 transmissions are known for durability, but heat management separates stock installations from ones built to last through years of demanding use.

The Specialty Products Company pan is a verified drop-in replacement for any TH400 application where OEM or budget economy pans fall short on cooling performance. Stock pans offer minimal thermal management; finned aftermarket units like this one reduce transmission operating temperature by 10–20°F under load, a measurable difference that improves shift quality, seal longevity, and overall reliability in marine or high-demand service.