I’ve only got 1300 miles on my 2024 so far and it’s proving out exactly the way my 2018 Colorado ZR2 did. GM overgears their trucks to max their MPG rating on the EPA loop, but that rarely translates in the real world. To get the best MPG, you need to be in the sweet spot on the torque curve. If you’re below it, even nearly imperceptible grade changes will require more fuel fed into the engine to maintain speed.
I really wish they’d spec’d a 3:55 gear ratio in these. That would allow them to get better gas mileage in the 65-75 MPH range, rather than having to risk attracting the road pirates just to get peak efficiency.