vortec engines

I have the 6.0 liter in mine. It gets about 8.5 mpg towing and 16 mpg empty. It goes down if i go above 70 mph. Keep in mind mine is a 2005 with the old 4 speed automatic not a newer one with the 6 speed. It does a good job towing my TT. I am looking for a new truck and considered a diesel but I don't think it's worth it at this point. I'm not traveling the country yet.

thanks 1oldtruck that is the kind of info i am seeking

My truck 3500HD SRW is in sig (6.0 Vortec, 4:10 axle). For the past 30+k miles I have averaged 12.3 mpg mostly city. I get about 8.5 towing 12k lb fifth wheel. I can get 14.5 on hwy empty at 73 mph (if head wind isn't strong. I basically say I get 12 mpg not towing and 8 towing.
Steve

2013 2500HD with the 6.0. I must have a heavy foot (I do)since I only get about 8 towing and 14 not. These numbers are only slightly better than my 2007 and 2009 with the same engine.

2007 2500 HD 6.oL 3:73 w/6spd 6000# trailer
11 mpg towing
16-17 mpg highway
14 mpg combined use

I have the even older 7.4 liter 1 ton dually and I get 8 towing. It would take many years for the cost of a similar age/mileage diesel to break even.

Paul

We just got back from the coast. I didnt put it on paper but according to the computer we got 24 going from Stanton tx to Freeport. we got 23 coming back. We usually get 12 when towing. i dont know how accurate the computer is. I have a gravity flow tank and fill up as needed. when we get to the station to fill the tanks we generally put in 4 or five gallons more than the computer shows. some times but not often i put in what the computer shows. Again I am trying to see if the price for the diesel is justified. Thanks for your real world expierences

Truck in sig with a 1,500 lb pop up FWC camper on full time.
I have been seeing 12 in town and 14 to 15 highway.

I would opt for the 11s and above with the new frame, 6 speed and the 36 gallon tank on all bed lengths.
Great truck by the way.

I have the 2008 with the 6.0 and 3.73 gears. We just came back from a week long road trip from Florida to Kentucky and back. We averaged 9 to 10 MPG loaded. I found using tow/ haul mode and "manually" locking out 6th gear it would run between 2200 and 2400 RPM in 5th gear at 62 to 65MPH. It would jump to 3000 - 3200 in 4th gear climbing the grades, dropping down to sometimes 55 MPH.

Empty around town I still only get 10 MPG and around 15 highway.

6.0L/6-spd/3.73 in SUV shape. We have almost 30k miles now in a little over a year and a half. We get 7-10mpg towing at 65-70mph, 13.5mpg mixed daily driving, and as high as 17.7mpg not towing on the highway. We love it!