TCI 228000 TH400 Cast Aluminum Deep Transmission Pan

TCI part number 228000 is a cast aluminum deep sump pan for the GM Turbo 400 (TH400/3L80) automatic. It holds roughly two quarts more fluid than the factory stamped steel pan and carries cast cooling fins across the outside, so the extra fluid volume and the added surface area work together to pull heat out of the sump. That matters on a Turbo 400 living behind a big block, in a tow rig, or in a car that spends time on a converter, because fluid temperature is what kills a TH400 long before the hard parts give up.

The pan is machined flat on the sealing surface and is noticeably thicker than a stock or reproduction stamped pan, so the rail does not oil-can when you torque the bolts and it stops the classic weeping pan gasket leak on an older case. The thicker rail also stiffens the bottom of the transmission case. A magnetic drain plug is fitted, so fluid changes are a matter of pulling the plug and letting the sump drain instead of breaking the whole pan loose and wearing the fluid. The magnet holds the fine clutch and steel material that normally rides around in the sump.

Fitment is GM TH400 / Turbo 400 / 3L80 automatic transmissions. The kit ships with a gasket and stainless steel mounting hardware, so you are not re-using rusted factory bolts on a fresh gasket. Note that with the added depth you lose some ground clearance under the pan, so check clearance on a lowered car or anything that sees rocks. Run the correct fluid level after installation, with the extra capacity accounted for on the dipstick reading at operating temperature.