My truck in "auto" mode always shifts into 6th right at 40mph and I've noticed I get noticeably better mileage in 6th at that speed. Most of the roads around me are 35-45mph speed limits so I just have always been in 6th and I get decent mileage. In fact, with my daily commute in Houston, which I probably average 35-40mph on the entire commute with heavy traffic, I don't see anything below about 14.0mpg on average.
---------- Post added at 12:10 PM ---------- Previous post was at 12:06 PM ----------
Press the + on the shifter and the gears will display....
To add to this, you can also "Lock Out" gears by hitting the "-" on the gear selector. If you want to force a downshift, you can hit the "-" and select that gear and punch it to pass somebody.
Yes, this works in Auto mode...the difference is if you "unlock" the gear by hitting "+" all the way back to showing all of the gears on the dash, it will shift into the gear it feels appropriate - not necessarily the next gear (it might go from say 3rd to 5th and just blow right through 4th). I don't know if this makes sense typing it out, but it makes sense in my head lol