Finned cast aluminum deep sump pan for the GM TH400/Turbo 400 that adds two quarts of fluid, drops operating temp, and drains through a magnetic plug.
A Turbo 400 behind a big block, in a tow rig or a motorhome, or in a street car with a loose converter makes a lot of heat, and the thin stamped factory pan is often the spot that seeps at the bolt rail. The TCI 228000 replaces it with a finned cast aluminum deep sump that holds two more quarts and drains through a magnetic plug. It is a bolt-on for GM TH400, Turbo 400 and 3L80 cases, and TCI says the stock dipstick needs no changes.
The pan is the reservoir the TH400's gear-type front pump draws from through the filter and intake pipe. More fluid in the sump means more oil sharing the heat load from the clutches and converter, and more time for the cooler to bring the temperature down before the same fluid is used again. The cast fins add surface area in the airflow under the car. TCI also notes the thick casting adds strength and rigidity to the bottom of the case, and a cast rail does not dish in between bolts the way a stamped rail can.
In the box you get the pan, a magnetic drain plug, a fluid pickup extension so the filter still sits at the bottom of the deeper sump, a filter, a pan gasket, and new rail bolts and washers.
Wipe the rail clean, run the vehicle to temperature and look for the actual leak point; GM's manual warns airflow can make a front or extension leak look like a pan leak. If the fluid is already burnt or full of clutch material, the pan will not fix that, so read our TH400 filter and pan service guide and the TH400 common problems guide first. A good cooler matters as much as sump volume; see the TH400 cooler line guide.
TCI part 228000 fits the GM Turbo Hydra-Matic 400, also called the TH400, Turbo 400 and 3L80, in GM cars, trucks, vans and motorhomes and in engine-swap builds that use a TH400. It does not fit the TH350, 700R4 or 4L80E; the 4L80E has its own TCI pan. The added depth costs some ground clearance, so check under a lowered car or an off-road truck before you install it. If you are not sure you have a TH400, the irregular pan outline and the TH350 vs TH400 identification guide will settle it. More parts are in the TH400 collection.
If the old pan showed heavy clutch debris, plan for a TH400 overhaul kit or a master rebuild kit rather than just new fluid.
| Part Number | |
| Brand | |
| Fitment | |
| Material | |
| Added Capacity | |
| Drain Plug | |
| Included | |
| Weight | |
| Origin |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
TCI rates it at two quarts more than the stock TH400 pan. Add that on the refill and check the level hot.
No. TCI states no changes to the stock dipstick are needed with this pan.
Yes. TCI includes a filter, a fluid pickup extension, a magnetic drain plug, the pan gasket, and new rail bolts and washers.
No. It is made for the TH400 / 3L80 case only. The TH350 and 4L80E use different pan patterns.
The GM service manual gives 12 lb-ft for TH400 pan bolts and 10 lb-ft for the filter retainer bolt.
