I am thinking of buying can anyone tell me what i can expect on fuel mileage towing and also around town not towing
any info would be great

Thanks,
Bamurf80

 

Truck in my sig. I keep it pretty loaded - two large tool boxes plus a ladder rack - averages an extra 1,350 pounds when I am "empty".

Around town mix of highway and back roads stays right around 10 MPG. +/- about 3/4 MPG depending on my right foot.

I have had one mostly unloaded highway only trip where I got 12 3/4 MPG. All my other highway miles have been towing the trailer in my pics - usually with 5 to 6 ATV's on board. One 2,500 mile trip averaged 8 MPG. Last year I did the same trip but removed the ladder rack and put on a bed cover - averaged 9.5 for this trip. All this at the posted speed limit, usually 60, 65 or 70 MPH.

I know several other guys with trucks rigged out like mine but they have the 6.0. They get better milage when empty but once loaded, actually get worse milage without the performance of the 8.1. BTW, mine is hooked to the Allison 5-speed tranny.

If milage is important and especially if you are going to tow a lot, I'd give serious consideration to getting a Duramax instead of the 8.1. I love my truck and the 8.1 is a great engine, but after the 900 series comes out in the HD versions I'll be trading.

Jaybee

 

I have an 2001 GMC Crew with the 8.1 and the Allison six speed. Empty, around town I get 9.5 to 10. On the highway it gets 11.5 to 13.5 mpg depending on my right foot. Pulling my 6500# travel trailer drops mielage to 8-9 range. I put a set of dual exhaust and Magnaflow mufflers and picked up only about 1/2 mpg. However, the sound of 500 cubic inches of V-8 power singing through the Magnflows is nearly spiritual for a gearhead such as myself. More amazing is the box frame and heavy duty construction. After five years it still does not have a single rattle.

 

[img]i/expressions/face-icon-small-sad.gif[/img]I have the 6.0 in my HD, Plenty of power but milage SUCKS!!! Going to go back to a 1/2 ton with a small V-8 before gas gets back to $3 gal. this summer.

 

Your tranny is a 5 speed. They didn't release the six speed version until this year.

Buck

 

Buck,
I double checked, you are correct the Allison is a 5 speed. Shows how much I know.

 

Hey, look at the brite side. This year it is a six speed. So in a wierd sort of way you are right. [img]i/expressions/face-icon-small-wink.gif[/img]

I just so happen to own a truck accessory store for a living. Knowing these trucks is my life. It's almost a sickness in my wife's eyes.
[img]i/expressions/face-icon-small-happy.gif[/img]

Buck

 

I have owned 2 GMC duramax with that allison and I think that they are ok unless you plan on pulling then they are junk. I have broke several allison transmission and so has a few friends. If you want a truck to drive around town and/or pull 26K lbs and still get great power and fuel mileage get a cummins with a manual 6 speed you will love it.
I get 20-25 mpg empty and around 16-17 pulling my 38' fithwheel. I can pull my 38' fithwheel all thew colorado and never loose more that 10 mph on ANY hill out there. I have also had 3 ford powerjokes and they are a joke also. Cummines is the way to go.

 

Too bad not one of the three trucks is made to tow 26k.

Buck

 

[img]i/expressions/face-icon-small-cool.gif[/img]Hated too. but traded in my '03 HD Crew Lb 6 ltr for a '04 Z-71 Ex/Sb 5.3 ltr. Really gonna miss the 8 ft. bed but hopefully a little gas savings!