2024 Gmc 3500hd Duramax Dually. Looking at a new 2024 at4 and just curious if the 10 speed transmission helps with mpg. I bought it just because over the 2500hd but pretty much guaranteed i'd never fully max the load capacity out for either.

Any faster then that the mpg goes down really fast. Explore the 2025 gmc sierra 2500 hd & 3500 hd denali luxury truck.