I have a 2009 ram 1500 qc with the 4.7l engine and this weekend I need to tow a reg. Cab s10 from Houston to Louisiana. So I was wondering when using the tow/haul mode which gear should I be using when cruising in the highway.
Tow/Haul disables torque convertor lockup (overdrive) and disables MDS (if you have it). Put the truck in Drive and the Tow/Haul mode puts it in 5th gear and changes shift patterns to maximize shift points.
I run this way with mine when towing my 30 foot trailer (8000lbs) until I'm on fairly level stretches of highway, then I'll turn Tow/Haul off. When I start getting into grades, I turn it back on.
You can leave it in Tow/Haul while you're towing - your fuel milage will be worse, but it won't hurt anything.