2025 Gmc Denali Ultimate Duramax Engine. Detailed specs and features for the 2025 gmc sierra 2500hd diesel denali ultimate including dimensions, horsepower, engine, capacity, fuel economy, transmission,. Explore the 2025 gmc sierra 2500 hd & 3500 hd denali luxury truck.
Meanwhile, customers can also opt for the 6.6l v8 l5p turbodiesel duramax engine, which is now rated at 470 horsepower at 2,800 rpm and 975 pound. Gmc is unveiling the 2025 sierra heavy duty and the first ever 2025 sierra hd denali ultimate, redefining the power and capability of this dominating truck.