Oldguy

I've been driving Dodge Cummins trucks since the 70's (6 of them) and just bought a 2011 Chevy 2500HD 4X4 6.0L extended cab standard bed truck. OMG...13.5 MPG hwy? I'm used to more like 23 MPG with 6.7L CTD. I had no idea these chevys were such gas pigs. I really like the looks and the interior (although its louder road noise than I expected). Three questions: 1. rear tire have to be inflated to 70 teeth jarring psi to keep the low tire warning cleared. Is that the reality? 2. anything I can do about the crappy mileage other than drive 50 mph on the freeway? 3. how can I tell what rear end gears I have? Thanks for any help you can give to get me re-acclimated to chevy.

country_09

Well goin from a 6.7 diesel to a 6.0 gas in the same weight class of trucks it's a no brainer mileage is definitely goin to suffer. Along with the fact that the truck is a literall brick goin down the road. You can do a custom tune but don't expect it to work wonders for you. Maybe 1-2 mpg at best. And to find out the gears, check the rpo codes in the glovebox door. GT4 is 3.73 and GT5 is 4.10s iirc

cleveland63b

how many miles does it have on it?

JK23112

I have a 2004 half-ton Silverado with the 5.3L and get 15 mpg in the city and maybe 18 or 18.5 on the highway -- and that is with the 3.73:1 axle ratio and 17" tires.

13.5 from a 6.0L 2500HD is about typical. Remember that a gasser doesn't have the low-RPM torque of a diesel, so running at a higher RPM will mean more fuel consumption. You cannot change stoichiometry or physics, sir.

cleveland63b

yea i didnt read close enough the first time, comparing diesel and gas in any form is not a good baseline

Oldguy

Thanks for the comments guys. I guess I had too high expectations of today's gas engines without doing my homework. Prior to buying my truck I asked a guy I know about his mileage (he has the same truck/engine, etc. only GMC). He said he gets 18 mpg highway and 15 or so in town. Same tranny, same engine, 3.73 rear end. His is an 08 with only 40,000 miles on it and mine is used 2011 with 48,000 miles. Anyway...I didn't check beyond his exaggeration before buying mine. I love it in nearly every other way...just surprised at the low mpg. I'll play poker with my GMC friend now because I know he's a bluffer.....

country_09

Lol definitely not gettin that in a 6.0 truck. My dads vmax 6.10, 4.10s) gets 13 all day every day

country_09

Lol definitely not gettin that in a 6.0 truck. My dads vmax (6.0 4.10s) gets 13 all day every day