Home Forums Hunting & Shooting Hunter's Campfire GMC 6.6 Duramax mileage?

For the guys that own them, what kind of mileage are you getting? Thanks!

My cousin has one. 3/4 ton 4x4. He gets 17-18 he said.

2024 3500 about 18’ish. As high as 21 but as low as 10/11 depending on the load. You could expect around 18 without a trailer.

I have heard pretty good on the newer ones...

I had a 2001 (?) with the LB7... it was a disaster.

FIL had a 06 model with 150k mi he said he just got it broke in and gettin 20mpg until some dumfuk took his front end off drivin wo headlights in at 5am🤦‍♂️

18 or so around town, and 24 on the highway. Helps if you don’t accelerate with a smoke cloud billowing out the pipes.

Mind is 2006, in town, short runs 11-14. Hwy unloaded 19 -- 21, depending on how fast it's going. Best mileage towing the boat to the coast and back, 17mpg. Boat and trailer are 3800 pounds. Mine is 100% stock, no mods..

20 on the interstate unloaded. 8-9 with 12-13k around home.

Average 11.8mpg in my 2019
3500 dually utility truck loaded with tools and tow a lot. Mix of interstate and local driving.
2019 mode
Pretty much same as my 6.0 gassers in same configuration. If it weren’t for towing equipment I’d go back to gas. Exhaust brake is worth the diesel alone.

Average 11.8mpg in my 2019
3500 dually utility truck loaded with tools and tow a lot. Mix of interstate and local driving.
2019 mode
Pretty much same as my 6.0 gassers in same configuration. If it weren’t for towing equipment I’d go back to gas. Exhaust brake is worth the diesel alone.

18/19 on my 2008 no load. 10/12 with trailer

Have 2 left ....not a lot of use anymore. 13-24 between town and high way.

But, But ......have had diesels since 1975. Will not own another.

They just do not pencil out.

I am on my second one. Current one is a 2013 denali. Gets 17.4 empty and 10.7 towing a 38 foot 5th wheel on flat ground.
Edit to add....towing without a head wind. We drove across indiana towing with a nasty head wind at 65 mph and got 7 mpg...lol

I have a 14. If I drive the speed limit it'll get high 19 ,low 20.
Most generally I'm over by at least 10 mph. So it's typically 18ish when not in town.
Pulling the fart box it gets 12-13.

Thanks guys!

Year?

The early 2007 might have been the best of the best. 20 MPG on semi-flat interstate. Maybe better now. But it sure went south for a decade.

Have a 2007 classic. 289,000 and is still my daily. 15-16 in town, 19-20 on highway.

The classics bring top$$

Last was a 2013 3500 dually. Got 14-16 running around. Right at 20 highway, about 10 pulling a 4 horse LQ trailer with 3 horses.

I just got rid of a 2006 LBZ; it had 160K on the odo. I was able to get 19-20 mpg on the interstate unloaded. Pulling a small trailer on the interstate, I'd get 14 mpg. Being a crew cab, the tank was smaller. I'd get about 375 miles on a tank of fuel made up of city/interstate driving.


Truck was all stock. Never been programmed and was running factory size tires.