I am about to close out a deal on a 2001 8.1L 2500HD. The truck is definitely a sweet truck. Didn't know if anyone here had any idea on what type of gas mileage to expect with the 8.1L? I have heard with the Allison transmission to expect similar to a 6.0L.

 

Just get the truck you won't regret it.... I actually have a 2001 8.1L 2500HD extended cab as well since it was new. I can honestly tell you I have never clocked the gas mileage to get an accurate measure. Some people look at me strange when I tell them that, like I've have my head in the sand or something, but it's mainpurpose was never aboutfuel economy.The truth is I bought the truck for a purpose to tow my 5th wheel plusI like the power on acceleration because of thetorque.Gas mileage to me was neverfactor and I'm no rich boy and Idon't make a million dollars either.(In 2001 when I bought itthe price of gas was still reasonable.) Not to mention driving conditions vary greatly depending where you drive and the type of driveryou are out on the road. If you put your leg into driving this bad boy you're gonna get there quickly but also burnsome fuel. If you don't blast aroundyou are probably going to be closer to the 6.0 as others have indicated.I will tell you that you are about to buy one of the best trucks I have ever owned. Do not hesistate, do not have second thoughts, just get the truck and enjoy it...

 

Gas mileage really wasn't the biggest concern of mine either. Most of my driving will be a mix of city/highway...mostly depending on what traffic is like. I won't be towing like other owners are towing campers. Mostly I was looking for a heavy duty truck and came across this one at a great value. I was just afraid I might be getting in over my head with a truck only getting me 10mpg.

 

I got an 02 2500 HD 4WD with the 6.0L Automatic a couple of months ago.I like the truck,plenty of power.I'm getting around 13mpg.

 

i have the 8.1 . went through the same thing... 6 or 8.1 heres how it turns out for me. i pull a bobcat and a 25' travel trailer. my freinds got the 99 Duramax turns out that off the line the 8.1 seems to pull better and easier... but on the open road doing 65 and comeing to the hill the duramax will pass the 8.1 however.... your question was 8.1 or 6 so i would suggest the 8.1

i get 12mpg with no towing. when i tow the travel trailer i get about 8.5/9 (i got to the mountians with it so its uphill all the way) the bob cat i dont really count gas cause its just around town anyway.. but pulls it all like crazy.

go for the 8

 

here here; 8.1l rules! I've had several Suburbans and the 8.1 and allison combo is the best truck by far. I don't pull much or haul heavy loads; so I too get strange looks for driving a 3/4 ton Suburban. For me it's safety (sitting up higher than a car); 4 wheel for bad weather; and now a engine that responses when I push the gas. I knew I had the right truck when I did have all 8 seats occupied and the back end with luggage; up a longer on ramp to an interstate and I got questioned why I was "racing" when my foot was only 1/2 way down the pedal....whooohooo! Around town and or heavy acceleration is 10-11 mpg; on the freeway and behaving; 13-14. And yes ;the truck is stock (not for long)