2025 Denali Duramax 2025. Detailed specs and features for the 2025 gmc sierra 2500hd diesel denali ultimate including dimensions, horsepower, engine, capacity, fuel economy, transmission, engine. 470 hp @ 2,800 rpm;.
We also learn about the l5p duramax engine utilizing improved engine braking through a more potent turbo vane actuator, upgraded valve springs, and the. Carbuzz tested a sierra 1500 denali ultimate with the optional duramax engine, one of the few diesel trucks left on the market now that ram killed the ecodiesel.