30 foot travel trailer at 80 miles an hour i was getting 3mpg on flat land... little over my tow rating. lol with the truck weighing in at 7500 pounds its self and trailer is 4500 pounds dry had both 50 gallon water tanks full

 

God damn, 3mpg!!!

 

cuz you were doing 80 instead of 60

 

You should be okay. To find out exactly what your towing capacity is go to www.trailerlife.com then select the TECH tab. TOW RATINGS is the third selection down. The next page after that selection will let you choose your year. The page that comes up will have all the major makes, cab, engine, and drive-train combinations.

Depending on the exact specifics of your truck it can vary by a 1,000 lbs, but it looks like you are in the 8,000 lb. range. I suppose the big air dam shape of your trailer hurts your gas mileage, but it should still be better. Do you have 4.10 gears?

I know my Avalanche got sway bars and air bags to keep it stable for a 6,400 lb car trailer combination. My Avalanche weighs 5,800 lbs empty.

 

nope 3.73's and it say's tow rating 8200 pounds

 

Damn that sucks!! i have an 05 1500HD and i usually get 9-10 pulling our 31 footer which i scaled at just under 8000 lbs, lifted on 35's with the 4.10 gears. does 65 at 2000RPM.

 

damn that is terrible i pull a 25ft sierra sport and i do pretty damn good, cruisin down the highway and get around 9 mpg

 

ya my 1500hd was not impressive this weekend either i have a magnacharger and i was towing a car hauler deck with a 53chev 5window pickup and a quad and it was all i could do to maintain 70 and most of the time i was at 5lbs of boost used about 250liters of fuel for 600km

 

yeah i don't get it empty with just my tools and tool box i get like 650 km to a tank of fuel... damn thing time for a DMax

 

you know you've reached your limit when the trans falls out