Comments sought from Silverado and Sierra Owners

[Nick B]

Am looking for information from people who watch their fuel consumption. Looking to establish real world figures, from any given engine size, and with any given trailer weight. Obviously gas consumption is much higher when towing but I'm sure that gas consumption for trucks without trailer is 5.3L, 4.8L then 6.0L is in that order, best to worse. But I'm guessing it's a different story when towing, and that the bigger motors give the best fuel consumption.

So, fellow GM drivers, please tell me what you know. Based on Canadian gallons, my 2008 4.8L Sierra gives me about 22mpg real world highway consumption, but towing 5,000 lbs of travel trailer, I'm lucky to get 10 mpg. What do you get?

Thanks,
Nick B

[CJBROWN]

My duramax was a '04. It was said on the durmax forums they got the best mileage of any of them. I ran hypertune stage 3. It would get 22-23 empty and 14 towing 5K lbs. Sometimes I would switch it to stage 2 for towing due to stock exhaust and fear of over temp on EGT's.

Killer truck, best one I ever owned. Don't have the boat anymore so it sold. But it would tow that silly boat up the pass at 85 if you wanted to. Stupid torque and horsepower. The newer ones are already chipped to those settings, but don't get quite the same mileage due to emmissions crap.

[FamFun4 u]

I have a 94 6.5 TD that gets 17-18 empty and 13-14 towing 10,000 lbs. it's a 3500 DRW extended cab long bed. Best 5 grand I ever spent. Only has a 85 mph speedo, but I don't mind. Getting ready for retirement in a couple years. Going to be the one leading the traffic jam.

[rlwithrow]

I have an 8000 pound 5th wheel that I started pulling with my 2000 Chevy 3500 with the 350 motor and automatic tranny and it got an average of 8 MPG on camper duty but 15 MPG empty. The truck was slow in the hills but on flat ground it would keep up with traffic. I have an '03 GMC Sierra 2500 HD with the 8.1 and Allison now for the camper and it also is getting an average 8 MPG towing and 11.8 unloaded. I just set the cruise on the 8.1 and let it do what it needs to and have never seen the tach go over 3200 RPM when climbing a grade.

[Zogg]

I had a 2010 gmc hd 6.0 gas truck.....hated the ride, seats hurt my back, and mpg was bad all around

I got 11.5 as a daily driver and 7 to 7.5 mpg towing 8000 pounds at 65 mph......

Bought a new ram a and get 22+ mpg highway....9-10 towing the same trailer.....

[Kingw2001]

Have an 05 silverado with 6.0 towing 12k 5th and get 7.5-8 mpg not towing I get 13.5 mpg

[NFlcamper]

Last truck was an 04 GMC extended cab regular bed Z71 half ton. Had 3.73 gears with the 4 speed auto and 5.3l. Real world numbers were;
Solo;
Best highway 16.5 MPG keeping under 55 (overseas highway in the Keys).
Highway 15-16
Around town 13.5
Towing an enclosed motorcycle trailer @ about 70 MPH;
11.5
Towing my 27' toyhauler @ 9400# keeping it under 63 mph - 9 mpg
Over 65 MPH - 7 MPG

Hope these numbers help.

[pitcrew18]

2012 6.6 diesel in a 3500 dually current mileage around 15.5 around town and 10 mpg pulling 16 k fiver.

[Passin Thru]

06 Duramax, 6 spd Allison, Edge tuner, added 60 hp, get 17.5 on the interstate at 75 MPH. Tow a Northwood Arctic Fox TT, GCVW is 19,000 lb, 10.9 MPG VA to CO, 10.8 CO-VA. 67 MPH is where is seems to run best, keep the button in on the Torque Converter and manually down shift at 2500 RPM.

[Bumps]

My 2005 GMC w/ 5.3L gets a reliable 16mpg empty (almost 200K miles now). Towing 4500 pounds drops it by 5mpg to just a hair over 11mpg. Oddly, dropping it into 4WD doesn't make a big difference in the mpg when towing. \ken

[fvstringpicker]

My 2007 GMC, 2500 Duramax. 19-20 mpg empty, 10-11 mpg pulling a 9,000 lb TT, 10-11 mpg pulling a 5,000 TT, and 14-15 mpg towing 15,000 lbs of steel on lowboy trailer. (measured w/less than 100 miles) Wind resistance is a major factor. Based on my talks with other Dmax owners and other diesel owners towing TT, it appears 10 mpg is about par.

[VanDiemen23]

2001 GMC K2500HD, 8.1, 4.11s pulling a 8,000lb toyhauler. 8.5 on flat ground. 6.5 to 7.5 avg for all the mixed uphill/downhills out in the mojave. On hot days when the fan comes on, lose 1 MPG.

[349]

Sig vehicles......Best ever mpg highway 24.2 empty,
towing 13000 lbs over the coquhalla both ways 11 mpg. (Canadian gallons)

[Akcontender]

2004 2500HD GMC with a 6.0 gas. I get 11.5 empty and 8 pulling a heavy 3 axle trailer with 4 snowmobiles on it. It is a 4 door short bed and it rides like a tank.