tow mileage with gm 6.0

I get 7-8 up to about 14k on mostly level ground in a 2015 3500HD

Mines not a GM but I get 7-8 mpg towing 12k with my truck.

Gm 6.0 with 3.73 (2009)
Empty: 13.5-15 city 16-17 hwy at 70mph
Loaded (see sig) 8.5 mpg florida. Mountain at 7.5-8.0 mpg but then back to 8.5
Love the truck regardless, this is my 2nd GM 6.0 and have been pleased. Pulled with both gas and diesel but chose gas. Love the 6 speed auto, and love the 4x4 option, best truck that I have had to date. Extremely reliable and easy to maintain, very little problems ever with this drivetrain.

Based on the fact that I get 7-9 mpg towing a much lighter travel trailer with a similar pickup, I would expect your fuel mileage to be in the 6-7 range. Just hope gasoline stays under $2.50/gallon.

I have a 2014 GMC, 6.0 and 4:10 rear end, I'm getting a disappointing 8 mpg. I was hoping for more but it is what it is. I'm pulling about 11, 000 mostly in Michigan's flatland.

2015 6.0 with 4.10 pulling approx 10k gooseneck for work gets 6-7. Gets aprrox 12 empty.

Thanks fof the replies. About what I expected. I'm getting about 11 with my diesel, and of course diesel is much more than gas, usually 40 to 50 cents a gallon. So fuel cost is actually pretty much a non issue. The best thing about my truck is that with the auxiliary in bed tank I can go about 500 miles between fuel stops. Also easier to use big rig pumps rather that trying to get in and out of gas pumps. But we have done it before when we had a gas motor home pulling a Colorado, which got 6mpg on a good day.

2009 Chev 6.0; 4.10; base WT; Extended Cab; 8' box. 8-9 mpg towing 11k 5th wheel.

7-10mpg depending on speed and winds with 6.0L/3.73. Unloaded it's 14mpg mixed summer, 12mpg winter and up to 18mpg highway non-towing. We really like ours.

Have an 09 with the 6.0 and 4.10s. 8-9 when towing, maybe 10 with a tail wind. Previously pulled a fiver, now pulling a 23' from the hitch.Same mileage. Motor is strong and love the 6 speed.