TH400 Turbo 400 Racing Transmission Filter and Pan Gasket Set

The TH400, GM's Turbo Hydra-Matic 400, is the three-speed automatic that lived behind big-blocks in trucks, Corvettes, muscle cars and full-size GM cars from the mid-1960s on. Every fluid service starts at the pan, and the filter that bolts to the pump pickup is what stands between the oil pump and whatever clutch material and steel have settled into the pan. This TCI racing kit swaps the stock felt/paper filter for a fine steel mesh screen and pairs it with a reusable pan gasket, so you pull the pan, drop the old filter, and reseal it in one pass.

The point of a mesh screen instead of paper is flow. A paper element filters smaller particles but chokes fluid flow as it loads up, and on a high-stall or hard-worked TH400 that restriction can starve the pump right when line pressure matters most. The steel screen trades some fine filtration for a much freer flow path, which is why it shows up in race and high-performance builds and in trucks running a converter with more stall. On a mostly-stock street transmission the paper filter is fine; step up to this when you are building for heat, load, or a looser converter.

It fits the GM TH400 (also badged TH400, Turbo 400, and later 3L80) from 1966 through 1991. The kit is the filter screen plus the pan gasket only - it is not a full rebuild or reseal kit, so a fresh front pump seal, modulator, and o-rings still come from a gasket-and-seal set if you are going deeper than a pan drop. The gasket is a reusable style, so seat it flat and torque the pan bolts evenly in a cross pattern; do not run a bead of RTV over it.