Genuine Allison 29536522 Deep Transmission Pan, 1000 Series

This is the genuine Allison OEM deep sump pan, part number 29536522, for the Allison 1000 Series automatic behind Duramax and other GM heavy-duty applications. It replaces the shallow factory pan and drops the sump about an inch, adding roughly three extra quarts of fluid to the system. More fluid means more thermal mass, so the transmission runs cooler under load and the ATF cycles less often through its heat range.

That extra capacity matters most when you tow, haul, run off-road, or push a tuned truck, where a stock shallow pan lets fluid temperature climb fast on long grades. Keeping the fluid cooler is the single cheapest thing you can do to extend clutch and seal life on a 1000 Series, which is why deep pans are the first upgrade most Allison owners make.

The pan is stamped steel built to Allison factory specs, so it bolts up as a direct-fit replacement with no modification. One important note: a deep pan needs the matching deep-pan filter (Allison 29542824 or equivalent) so the pickup reaches the new sump floor; the standard shallow filter will sit too high. Reuse or replace your pan gasket per your service procedure.