2024 Duramax Fuel Mileage Calculator. I have 12,000 mile on a 2022 3500 gmc duramax, 10 speed 3:42 dually rear end 4×4, terrible mileage. With the 2024 duramax, the excitement and potential for upgrades are higher than ever since its debut.

It is calculated by weighting the city value by 55% and the highway value by 45%. Looking at a new 2024 at4 and just curious if the 10 speed transmission helps with mpg.