10L1000 Transmission Service Kit with Fluid and Filters

Everything a 10L1000 service takes in one box: three gallons (12 quarts) of DEXRON-ULV automatic transmission fluid and the DF-434 filter kit, which replaces GM 24298004. It fits the Chevrolet Silverado and GMC Sierra 2500HD and 3500HD with the 6.6L Duramax and the 10L1000 ten-speed, 2020 through 2025.

DEXRON-ULV is not interchangeable with Dexron VI. It is the ultra-low-viscosity fluid GM specifies for the 10L1000, and running the heavier fluid in this unit changes clutch apply timing and line pressure behavior. If you have ever topped one of these off with whatever was on the shelf and then chased a soft 4-5 shift or a shudder on light throttle, that is the reason to buy the fluid and the filter as a matched set rather than piecing it together.

Bench notes: three gallons is the quantity for a pan drop and filter change, not a full exchange. A complete flush through the cooler lines takes noticeably more fluid, so order a second kit or extra fluid if that is the job. Service these trucks level, drop the pan slowly because it holds fluid at the rear, change the filters in the kit, torque the pan bolts in sequence, then fill and set the level at operating temperature with the engine running and the selector cycled through the gears.

Heavy-duty trucks that tow are the ones that punish this transmission. GM's severe-service interval is much shorter than the normal-service interval, and a 10L1000 that spends its life behind a gooseneck earns the shorter one.