Major fleets see 9-10 MPG pretty commonly when used on the highway at sane (less than maximum legal) speeds. In town an AT will generally get better mileage and performance but opposite on the interstate.

Mileage will be lower than with a pickup I would think, but you can theoretically haul more so you should end up ahead.

 

Any used truck you find will most likely need some mods to make a good hauler out of. Depends on whether you are mostly over the road or local stuff. Not hauling a lot of weight and a higher hp DT with a good rear gear will get decent mpg.

 

Its mostly over the road but regional. Majority is interstate driving with a few miles down a back road. Im comfortable with a few mods since ive been working on diesels since I was about 12 and I now know where to find the info that I need.

What rear should I be looking for? I was thinking 4.10 should be about right but im not sure.

 

The gears depend on the tires and transmission.

You *want* 11R22.5 rubber and a trans with an OD or two. But for a good driver on the highway, you won't necessarily want an AT, the only way to get two ODs.

The cruise RPM should be in the 1800-2000 RPM range at whatever speed you want to drive it. Therefore, the real answer is... it depends.

 

I have a direct high gear 6 +1 with 3.21 gears and 10R22.5 (39" tires). Turns 1700 @ 65 and gets about 9 - 10 mpg at 35,000 - 40,000 GCW.

DT 250 turned up to 275+

 

That sounds perfect! Thats what I will start looking for. I dont think I will be anywhere near that about of weight either. Does she pull up hills pretty good with such a high rear?

 

With 1700 RPM @ 65 MPH you can drop a gear and go!