Cast aluminum deep pan for GM 4L80E and 4L85E that adds two quarts of fluid, cooling fins, and a magnetic drain plug for a cooler-running transmission.
If your Silverado or Sierra 2500, Suburban 2500, Express or Savana van, or a 4L80E-swapped hot rod is throwing a TRANSMISSION HOT warning on long pulls, or the stamped factory pan keeps weeping at the bolt flange, the TCI 278000 is the usual fix. It is a cast aluminum deep-sump pan for the GM 4L80E and 4L85E that holds about two extra quarts of fluid, carries cooling ribs on the outside, and has a drain plug so routine services stop being a messy pan drop.
The 4L80E is a heavy-duty four-speed built for three-quarter and one-ton trucks, and most of the work it does, towing and hauling, turns into heat. The pan is the reservoir the pump draws from, so every extra quart in it is more fluid sharing that heat load and more time for the cooler to pull temperature down before the same oil goes back through the clutches. The ribbed casting adds surface area for the airflow under the truck, and the thicker walls do not flex the way the thin stamped pan does when it is torqued against the case. That flex is what lets stamped pans leak at the gasket after a few heat cycles. TCI also notes the extra material stiffens the bottom of the transmission case.
A deep pan helps a healthy transmission run cooler. It will not cure a slipping one, and slip itself makes heat. Watch transmission temperature on a scan tool or gauge during a typical tow. If it climbs while shifts stay firm and there are no codes, extra capacity and a good cooler are the answer. If temperature spikes along with flare, late shifts or converter slip codes, diagnose that first using our 4L80E common problems and fixes guide. Low line pressure from a weak EPC solenoid can mimic a heat problem; 4L80E pressure control solenoid symptoms walks through how to tell.
The 278000 fits every GM 4L80E and 4L85E, which covers 1991 through 2009 Chevrolet and GMC 2500 and 3500 pickups, the Suburban 2500, Express and Savana vans, the Hummer H1, and 4L80E swaps. The pan bolt pattern did not change across those years. What does change is the space under the truck. The deeper sump sits closer to the crossmember, and on some 3/4-ton chassis and on lowered trucks that gap gets tight. Measure from the bottom of your current pan to the crossmember and exhaust before you order. If it is close, send us your year and VIN and we will check it. See all of our 4L80E parts for the rest of your service.
| Fitment | GM 4L80E, 4L85E automatic |
| Material | Cast aluminum with cooling fins |
| Added Capacity | Approx. 2 extra quarts |
| Drain Plug | Magnetic, bolt-out for fluid changes |
| Hardware | Stainless steel hex bolts, gasket, two filters included |
| Part Number | TCI 278000, Made in USA |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
About two quarts over the stock 4L80E pan. Fill to the factory amount, add roughly two more, then set the final level with the fluid hot and the engine running in Park.
It bolts to every 4L80E and 4L85E case. The only fitment question is clearance under the truck, because the sump is deeper. On some 3/4-ton chassis and lowered trucks the crossmember sits close, so measure before ordering or send us your year and VIN.
Yes. TCI includes two filters of slightly different heights, plus a gasket and stainless hardware. Test fit both and use the one that seats firmly in the case.
It adds capacity and cooling area, which lowers temperature on a healthy unit. If the transmission is slipping or the converter clutch is not locking, that slip makes heat and has to be fixed first.
DEXRON-VI, which is what GM lists for the 4L80E in the 2008 Express owner manual. Older manuals listed DEXRON-III, which is no longer the current GM fill, so check your manual and use current DEXRON-VI fluid when you service it.
