To shift or not to shift

[cwsoules]

My 2000 Dodge with a cummins diesel and 4:10 rear end gets, when towing a 10.4K 5er, reliably over 10 to 11 mpg on fairly level ground. In the mountains it will drop to 9.5 and on flat land I have seen up to 13 mpg with a tail wind.

[MADDOG`]

I'm "shiftless" so I like an auto. And the GM DuraMax/Allison combo is a dream!

[TowBoss]

Well, I know the 6.0 Ford has a deserved bad rap, but I think Ford got most of the kinks out. I looked at all the TSBs before I bought mine, and after 05, most of the drivetrain TSBs went away. That's what made me feel better about buying a Ford. I only have 2800 miles on mine, but I've been towing some pretty good grades in that time and haven't had a problem. I get 7 mpg towing lots of grades in a headwind, and 9.5 - 10 mpg on flats. That's with a 17k 5er and 4.30 gears going 65-70 mph. Also, I went with an auto. I would have purchased a Duramax/Allison, but you can only get 3.73s in the dually. I don't know why chevy did that, but that's really what it came down to. Good look on whatever you purchase.