I know a lot depends on driving habits and load. But what MPG's should I expect to see with my F-350 dually?

With my 7.3L F-250 and Excursion in see 13-15 MPG's around town and 16-18 on the highway doing 70 mph. Towing varies with weight and wind speed.

But with the 6.0L dually and 4.10 rear, I see 10.5 - 11 MPG's at 70 mph according to the dash display. Doesn't vary much this first month I have owned the vehicle.
Just curious what others are seeing……

 

I tow and daily drive with mine and average about the same as you with mixed towing. My 5th wheel rv is about 12,000 and a flat with an average load weighs 9,000. 2 things killing you is thr 4.10 ratio and 70, 70+ mph. your other trucks are lighter and higher gear ratio, probably 3.73, so naturally will get better mpg.
I don't see what year your dually is but the later program flashes yielded the worst mpg. I'm in the process now getting tunes to see if it helps my mpg.
Also, don't trust the computer. Fill your tank and reset the odometer trip. Run the tank as low as you can comfortably and then refill at the same station in the same manner as the initial fill. Log the miles and gallons. Divide the miles by the gallons and that will give you average MPG. ex: 400 miles / 40 gal = 10mpg

 

According to the book, I know who reads that thing, the MPG is based on the last 500 miles of driving. If I pull my camper it starts to creep down but it will be off by 3-4 mpg's when going less than 100 miles to the CG. You can press and hold the reset button to clear it.

 

Yep, the other two have 3.73's. So on those I am at 2000 rpm's at 70 mph. Our 6.0L is a 2006.

Just was wondering what MPG I should expect.
I'm in the same boat with our 5th wheel. 38+ feet and weighs close to 11K empty. Towing with the dually is so much nicer. I really like this setup.....just need to get a few more things straight on the truck. Looking forward to some long road trips with it next year……

 

Cool, didn't realize that.....thanks