I need to buy a different truck this year (used) and I was wondering what you guys are seeing for real world gas mileage numbers. I am not interested in a diesel at this time. I am talking about the 6.0 and the 8.1 with the Allison trans. The trucks will be either extended cab or crew cab 4 X 4 models. Most likely 3.73 gears.

Thanks

6.0 3/4 suburban

10 city 13 hwy

towing 8500# 9

I just bount (pick it up tomorrow) a 04 Crew Cab 4x4 with the 6.0 and 4:10 gear. I will let you know mileage numbers next week. Everyone I talked to said the 8.1 is so hard on gas it just is not worth it. It is also not very common. I think it depends on if the truck will be used for every day driving of just towing.
I was told that I can expect 15 and 17 when not towing.

I just bought an '04 Avalanche 2500 with 8.1 Vortech/4L85E tranny/4.10 rear diff and average 11 mpg with half interstate and half suburb driving. With a 37 gallon tank I have almost a 400 mile range per tank and $60 each fill up.

I have an 02' chevy 2500HD with the 8.1 and allison trans... I get about 11 MPG city and about 13 MPG highway not towing anything... less of course with a load... not all that great to say the least...

Dad had an 01 2500 4X4 ex cab 6.0L with 4.10 gears and pretty much got 11mpg all the time city or highway.

so far have averaged 12 mpg for 10,000 miles on my crew cab 4x4 with 3.73's. Sucks more fuel than my 5.7 ever did.

I need my Suburban so the mileage doesnt matter! Besides I can haul 9 a$$es anywhere in it

My cousin has an 01 2500 4x4 with a 6.0. He says he gets 13 on the highway, and isn't real happy about it either.

I HAVE AN 03 SUBURBAN 8.1 373 GEAR . FROM MARYLAND TO KEY WEST WITH 9000 OR SO LBS. BOAT GOT 9MPG UNLOADED 13MPG . I WOULD GO WITH THE 8.1 -373 GEAR OVER THE 6.0. 6.0 WITH 373 IS UNDER POWERED , 6.0 WITH 4.10 SAME MPG AS 8.1 373 BUT NO BIG BLOCK TORQUE.