Genuine Allison 1000 deep sump pan 29536522 with the deep internal filter 29542824 and spin-on 29539579, adding about 3 quarts of capacity.
Towing heavy with a Duramax and an Allison 1000 means the transmission spends a lot of time hot, and the factory shallow pan on a GM pickup holds less fluid than the Allison 1000/2000 was designed to carry in a standard sump. This kit puts the genuine Allison deep sump pan (29536522) on the truck along with the two filters it needs: the deep internal suction filter (29542824) and the spin-on control main filter (29539579). It is the setup owners look for when the transmission temperature climbs on long grades, when they want more fluid in reserve for heavy trailer work, or when they are already doing a fluid and filter service and want to do it once.
The Allison 1000 draws fluid from the pan through the internal suction filter into the pump, then sends it through the spin-on control main filter on the side of the case before it reaches the valve body and clutches. More fluid in the sump means more thermal mass to absorb heat between trips through the cooler. Allison's own capacity table in its fluid and filter recommendations bulletin lists the standard sump at about 10.6 quarts on a refill versus about 7.4 quarts for the shallow sump, which is where the roughly three-quart gain on this conversion comes from. The deeper sump also keeps the filter inlet covered when the truck is nose-up on a ramp or a steep launch.
Check your fluid level correctly before assuming a heat problem is the pan. Allison's operator's manual says the hot check is done after the sump reaches 160-200 F with the engine at idle on level ground, and a level that is low or overfull will cause overheating on its own. Look at what is in the old pan and filter as well; friction material or a lot of metal means the deep pan is not the fix and the transmission needs closer inspection. Our Allison 1000 fluid and filter service guide covers real capacities and intervals, and the TCC shudder diagnosis guide helps if heat has already started to affect converter lockup.
The kit is listed for the Allison 1000 Series (and 2000 Series units sharing the same pan rail) from 2001 on, including Chevrolet Silverado and GMC Sierra 2500HD and 3500HD trucks with the 6.6L Duramax, plus GM medium-duty chassis. In GM HD pickups the Allison 1000 ran through 2019; 2020 and later HD pickups use the 10L1000, a different transmission, so this kit is not for them. Because the internal filter has to reach the bottom of the deeper pan, run the deep filter (29542824) included here; the shallow filter (29542833 or 29537965) will not reach. If you are not sure what your truck has, send your year and VIN, or browse the Allison 1000 parts collection.
Drain the fluid, remove the factory pan, and pull the old suction filter straight down off the pump inlet. Push the new deep filter on until the neck seats fully; a partly seated filter can draw air. The pan gasket is not included because the factory gasket is designed to be reused, so inspect yours and replace it if the bead is cut or flattened. Hang the deep pan and tighten the bolts evenly in a crisscross pattern. Spin on the new control main filter last; Allison lists about one pint of fluid lost at that filter alone. Fill with an Allison-approved TES 668 fluid such as TranSynd 668, plan on about three quarts more than your usual service, then set the final level on the dipstick hot. A truck that tows constantly also benefits from fresh cooler lines if the originals are seeping at the crimps.
| Pan part number | |
| Internal filter | |
| External filter | |
| Added capacity | |
| Fitment | |
| Gasket |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
About three quarts. Allison's capacity table lists roughly 10.6 quarts on a refill for the standard sump versus about 7.4 quarts for the shallow sump. Always set the final level on the dipstick hot.
No. The deep pan needs the deep suction filter, 29542824, which is included. A shallow filter (29542833 or 29537965) will not reach the bottom of the deeper pan.
No. The factory Allison pan gasket is reusable. Inspect it and reuse it if the sealing bead is intact; replace it if it is cut, flattened or leaking.
No. GM HD pickups from 2020 on use the 10L1000 ten-speed, not the Allison 1000. This kit is for Allison 1000/2000 Series transmissions.
An Allison-approved fluid. TES 668 fluids such as TranSynd 668 are Allison's current recommendation and are backward-compatible with older TES 295 fluids.
Not if the clutches are already worn. The deep pan helps control heat and keeps the filter covered. If the old filter shows friction material or the truck slips at normal temperature, diagnose the transmission first.
