Most of the areas I drive are up and down hills so it was always shifting. Didn't seem as bad with the cruise on but if it was very steep it would downshift into the lower gears and jump to the high rpms. Not near as bad with the tow/haul on. I did notice that it would downshift and use engine breaking coming into town but not on the rolling hills. Not sure about gas mileage yet as I haven't filled but looked as if I used less on this trip than on the last trip going to the same area.