Genuine Allison OEM deep sump pan for the 1000 Series; adds about 3 quarts of fluid to run cooler when towing or hauling. Requires a deep-pan filter.
Owners of Duramax-powered Silverado and Sierra 2500HD and 3500HD trucks shopping for a deep transmission pan usually have one of two reasons: the transmission temperature gauge climbs every time they tow up a long grade, or they want more fluid in reserve before they start pulling a heavy fifth wheel or tuning the engine. This is the genuine Allison deep sump pan, part number 29536522, the factory Allison piece rather than an aftermarket cast pan. It swaps in place of the shallow stamped pan that GM pickups left the factory with and brings the Allison 1000 up to the larger standard sump capacity.
The pan on an Allison 1000 is not just a cover. It is the reservoir the pump draws from through the internal suction filter, and the fluid sitting in it is what soaks up heat between passes through the radiator cooler. Allison publishes two sump sizes for the 1000 and 2000 Series. Its fluid and filter bulletin lists a refill of about 10.6 quarts for the standard sump and about 7.4 quarts for the shallow sump, so moving to this pan adds roughly three quarts. That extra volume slows how fast the fluid heats up under a sustained load and gives the pickup more margin when the truck is pointed steeply uphill. It does not add cooling capacity the way a bigger cooler does; it adds thermal mass and reserve.
A deep pan is a heat and reserve upgrade, not a repair for worn clutches. Check the fluid level the way Allison specifies: hot, at idle, on level ground, with the sump between 160 and 200 F. An overfilled or underfilled Allison will run hot on its own. Then look at what came out. Clean fluid and a clean filter mean the pan is a sensible upgrade. Clutch material, heavy metal or a slip at normal temperature mean you have an internal problem; start with our Allison 1000 valve body testing guide and the TCC shudder diagnosis guide.
This pan is listed for Allison 1000 Series automatics. In GM pickups that means the 2001-2019 Silverado and Sierra 2500HD and 3500HD with the Duramax or 8.1L, plus Allison 1000-equipped medium-duty chassis. The 2020 and newer HD pickups use the GM 10L1000 ten-speed and will not take this pan. Allison 2000 Series units share the same pan design in many applications, but confirm by matching your existing pan's bolt pattern before you order, or send us your year and VIN. You can see filters, fluid and hard parts for these trucks in the Allison 1000 parts collection.
The pan is only half the job. A deep pan needs the deep internal suction filter, Allison 29542824, because the shallow filters (29542833 or 29537965) sit too high to reach the new sump floor and will draw air. Our deep pan filter and gasket kit covers the deep filter, the spin-on control main filter and a pan gasket in one box. Plan on fluid as well: the swap takes about three quarts more than a normal service, and Allison's current recommended specification is TES 668, such as TranSynd 668 in a 3-gallon pail. The pan is stamped steel built to Allison specification, weighs about 8 lb, and bolts to the original pan rail with no modification.
| Part number | Allison 29536522 (genuine OEM) |
| Fits | Allison 1000 Series automatic transmissions |
| Added capacity | Approx. 3 extra quarts vs stock shallow pan |
| Extra depth | About 1 inch deeper than stock |
| Material | Stamped steel, Allison factory spec |
| Requires | Deep-pan filter (e.g. Allison 29542824) |
| Weight | 8.08 lb |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
About three quarts. Allison lists roughly 10.6 quarts on a refill for the standard sump and about 7.4 quarts for the shallow sump. Always set the final level on the dipstick with the transmission hot.
No. The deep pan requires the deep suction filter, Allison 29542824. The shallow filters, 29542833 and 29537965, will not reach the bottom of this pan.
Yes. This listing is the genuine Allison 29536522 stamped steel deep sump pan built to Allison specification.
No. GM HD pickups from 2020 on use the 10L1000 ten-speed. This pan fits Allison 1000 Series transmissions, which GM pickups used through 2019.
No. It adds fluid volume and pickup reserve so temperatures rise more slowly. A cooler removes heat. Trucks that tow heavy all the time often benefit from both.
