Allison 1000 Deep Transmission Pan 29536522 Duramax

This is the factory Allison deep sump pan, part number 29536522, for Allison 1000 Series automatics behind the 6.6L Duramax. It replaces the shallow stamped pan and picks up roughly three additional quarts of fluid capacity. More fluid in the sump means more thermal mass and a lower steady-state temperature, which is the single cheapest thing you can do for an Allison that spends its life pulling a trailer or running loaded in the hills.

Heat is what kills these units. Clutch material starts breaking down well before the fluid does, and a 1000 that lives at 220-plus degrees on a grade will show up on the bench with glazed clutches and a burnt C2. Dropping sump temperature 15 to 25 degrees under load will not fix a marginal build, but it buys real service life on a healthy one.

Installation is a straight swap onto the case with the stock bolt pattern, but you must run the DEEP pan filter, not the shallow one. The shallow filter neck will not reach the fluid in this pan and you will starve the pump. Plan on the deep-pan filter and a new pan gasket at the same time, and refill to the level indicated on the dipstick with the trans at temperature rather than by quart count, since deep pans throw off dry-fill math.

Stamped steel, machined sealing surface, built to Allison factory spec. Package dimensions 16.2 x 16.2 x 4 inches, 8.08 lb.