2024 Chevy 2024 Duramax Fuel. I go to the truck stop and fill the def from the fuel isle. But my new duramax's fuel economy is about 3 mpg less then my last 6.7 cummins.
In 2023, the duramax engine was retuned to provide more power, gained new pistons, a revised. I have heard the generation 1 l5p’s were much better in the fuel economy arena.