Genuine Allison OEM deep-sump pan for the 1000 Series behind the 6.6L Duramax; adds about 3 quarts of fluid to pull heat out when towing and hauling.
If you tow with a 2001-2019 Chevrolet Silverado or GMC Sierra 2500HD or 3500HD and watch the transmission temperature climb on every long grade, a bigger fluid charge is the simplest fix for the Allison 1000 behind your Duramax. This is the genuine Allison deep-sump pan, part number 29536522, sold on its own. It replaces the shallow pan GM fitted to its pickups, sits about an inch lower, and holds roughly three more quarts of fluid. If you want the pan with both filters in one box, see the Allison 1000 deep pan kit with filters.
The Allison 1000 Series was designed to run with either a shallow or a standard-depth sump, and GM pickups left the factory with the shallow version. Allison's fluid and filter recommendations bulletin lists the standard sump at about 10.6 quarts on a refill against about 7.4 quarts for the shallow sump. Fluid in the pan is thermal mass: every quart soaks up heat from the clutch packs and the converter between trips through the cooler, so a bigger sump takes longer to reach a damaging temperature and recovers faster on a downgrade. The extra depth also keeps the suction filter inlet submerged when the truck sits nose-up on a steep ramp or launches hard with a heavy trailer.
A deep pan adds margin. It will not cure a transmission that is already damaged or a fluid level that is wrong. Allison's operator's manual says the hot check is made with the sump at 160-200 F, the engine idling and the truck on level ground, and both low and high levels cause overheating on their own. When the old pan comes off, inspect what is in it. Fine gray paste is normal; friction material, flakes of metal or a heavy dark sludge mean the clutches need attention first. Our Allison 1000 fluid and filter service guide lists the real capacities and change intervals, and the TCC shudder diagnosis guide helps if heat has already started to affect lockup.
This pan fits the Allison 1000 Series used in 2001-2019 Silverado and Sierra 2500HD and 3500HD trucks with the 6.6L Duramax, and it shares the pan rail with the 2000 and 2400 Series. GM's 2020-and-newer HD pickups use the 10L1000 ten-speed, which is a different transmission, so this pan is not for them. Gas-engine HD trucks with the Allison 1000 use the same case, but confirm your transmission tag before ordering. If you are unsure, send your year and VIN and we will check it, or browse the Allison 1000 parts collection.
The deep pan must be paired with the deep suction filter, Allison 29542824. The shallow filters (29542833 or 29537965) are too short to reach the bottom of this pan, so do not reuse them. Drain the fluid, remove the shallow pan, and pull the old suction filter straight down off the pump inlet. Push the deep filter on until its neck is fully seated, because a partly seated filter draws air. Allison designs the pan gasket to be reused, so inspect the bead and replace it only if it is cut, flattened or swollen. Hang the pan and snug the bolts evenly in a crisscross pattern. Change the spin-on control main filter at the same time; a spin-on transmission filter is listed for this case. Refill with an Allison-approved TES 668 fluid such as TranSynd 668, allow for about three quarts more than a normal service, then set the final level hot.
| Type | Deep-sump transmission oil pan (genuine OEM) |
| Transmission | Allison 1000 Series (also 2000 / 2400 Series) |
| Part number | 29536522 |
| Vehicle fitment | 2001-2019 GM 6.6L Duramax, Silverado & Sierra 2500HD / 3500HD |
| Added capacity | Approx. 3 quarts over the stock shallow pan |
| Depth | Approx. 1 inch deeper than stock |
| Material | Stamped steel |
| Requires | Deep-pan internal filter 29542824 and new pan gasket (not included) |
| Brand | Allison Transmission (Genuine OEM) |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. This listing is the pan only. You need the deep suction filter 29542824, and the factory gasket can be reused if it is undamaged. For pan and filters together, choose our deep pan kit with filters.
No. The shallow filters, 29542833 and 29537965, are too short for the deeper pan and will not draw fluid correctly. Use the deep filter 29542824.
About three quarts. Allison lists roughly 10.6 quarts for a standard-sump refill against roughly 7.4 quarts for the shallow sump that GM pickups came with.
No. GM moved its 2020-and-newer HD pickups to the 10L1000 ten-speed, which is a different transmission with a different pan.
An Allison-approved fluid. Allison now lists TES 668 as its recommended specification for the 1000 Series. Set the level with the sump at 160-200 F.
It sits about an inch deeper than the shallow pan. Most owners fit it without trouble, but check clearance if your truck is lowered or runs an aftermarket skid plate.
