Real world Chevrolet 6.0 gas mileage in 2500 HD

[Copperhead]

Semi truck fuel economy has not gone up that much has it? I have a friend who hauls over length power poles and has a few trucks. His '91 Freightliner with a Detroit diesel gets 11 MPG loaded. His 2007 Freightliner with Detroit diesel gets 4 MPG. Our 1971 6x6 "Duece and a Half" with a white turbo diesel gets 10 MPG.

The lifetime average mpg on mine hovers right around 8 mpg. I have a 2013 semi truck, but I have a 2000 year build Detroit in it. I haul light and heavy with a 53' dry box trailer. Lots of bulk feed and bulk dried eggs, oatmeal, granola, etc. My average gross is right around the 65,000 lb that was mentioned. The heavy stuff, of course, gets close to 80,000 lb GCVW.

There are some operators that are doing will into 9 mpg territory with their semi trucks, and I know one that has a documented run from California to N. Carolina, grossing 72,000 lb, and busted 10 mpg average for the entire run. That is with a 2015 Freightliner Cascadia with a DD15 motor. That run was documented and confirmed by Freightliner.

Just based on those examples, it is not unreasonable to expect a 6.6L Dmax with a 5th wheel camper, that total would not exceed GCVR, to get a minimum of double the mpg at gross weight, or even more, than these semi trucks. After all, the semi motors are 2.5 times larger, the gross weight is 3-4 times as much. And when we factor in the total dimensions as well, the semi is displacing and fighting a lot more air and wind. And then there is the actual number of tires and the footprint they are placing on the ground, which has an effect on mpg as well. So I still contend, the pickup OEM's have really dropped the ball on what they could be getting for mpg in a 6.6L Dmax, or any other brand of pickup diesel in a 3/4 or 1 ton. They should be getting 20 mpg for an average while towing.

 

[Copperhead]

Best we got with our 03 was 15 to 16 puttering around and a bit better on long trips. Our 2015 with around 850 miles is averaging 12-13 as of now, no longer trips in the books yet

Fuel quality, terrain, altitude, driving style all play into it. These 2500/3500 pickups take up a lot more space externally nowadays and that affect mpg from an aerodynamic standpoint.

 

[MossRoad]

I also had a 77 Silverado with a 454 2 wheel drive. Like yours about 8-10 mpg, loaded/unloaded, air cond on /off, uphill/downhill didn't matter. But man did it have power, I could gain speed on ANY hill with my 30' fifth wheel and a atv trailer behind that.:thumbsup:

I remember turning right out of an alley leaving work one night. It had rained lightly and I was kind of in a hurry. I stepped on it too hard and I was facing 270 degrees left before I could stop it. I sometimes miss that raw power. On another note, it was rusting badly, floorboards were gone, it had straight pipes that ended under the cab and we just had a baby.... so it had to go.

 

[rmk700]

Question I have is why does the tranny have a 1st gear selection off by itself? What can it do that M1 doesn't?

Column shift goes PRNDM 1

I goggled this and looked in the manual and can't find anything on what the '1' is used for. I know it's a solo first gear but why?? It sure does seem to have the exact same function as 'M1'.

I thought maybe it has something to do with being in 4X4 low.

 

[dclynch]

I also had a 1985 extended cab F250 460 with 4:11 rear end. 7 MPG loaded or empty. One time when I really put a load on it I got 5 had dual 20 gallon tanks 100 miles each. (Ouch) but like others have said I pulled a 30' travel trailer and you never knew it was back there and if you wanted to pass you just pulled out and stepped on it. Couldn't keep exhaust manifold gaskets on it for some reason so I got rid of it.

 

[MossRoad]

I also had a 1985 extended cab F250 460 with 4:11 rear end. 7 MPG loaded or empty. One time when I really put a load on it I got 5 had dual 20 gallon tanks 100 miles each. (Ouch) but like others have said I pulled a 30' travel trailer and you never knew it was back there and if you wanted to pass you just pulled out and stepped on it. Couldn't keep exhaust manifold gaskets on it for some reason so I got rid of it.

A friend of mine's dad in high school was a brick mason. We'd work for him and he had a Ford with a 460. YIKES! Torque monster!!! And thirsty, too! :licking:

 

[sd455dan]

I also had a 1985 extended cab F250 460 with 4:11 rear end. 7 MPG loaded or empty. One time when I really put a load on it I got 5 had dual 20 gallon tanks 100 miles each. (Ouch) but like others have said I pulled a 30' travel trailer and you never knew it was back there and if you wanted to pass you just pulled out and stepped on it. Couldn't keep exhaust manifold gaskets on it for some reason so I got rid of it.

Wow that is kind of opposite what happened with our long box f350 2wd with the 460 it could get 16 hiway consistently, at the same time we had a 1979 Chev 2wd dually 454 4 speed with a flat bed- bought new. The chev would get about 10-11 loaded and never broke 12 empty. The chev was definitely lower geared and i am sure the dually didn't help.

 

[CJONE]

My GM 6.0 was one of the worst trucks I owned for mileage. The best it ever got was on trips and it was just under 14. The worst was plowing and it was in the 3 range. Most of my trucks that were gas were in the 6-7 range plowing. The good part is it ran and pulled very well but the gas mileage was a hard pill to swallow. A good friend has one and he gets 16 on the highway and 10-12 towing. CJ

 

[Beltman60]

the M1 is where the trany would start if you used it
you then have to use the + & - on the shifter to move it into the other gears to up shift and down shift

the M1 will change as you upshift to M2 then M3 ect

 

[C4Ranch]

the M1 is where the trany would start if you used it
you then have to use the + & - on the shifter to move it into the other gears to up shift and down shift

the M1 will change as you upshift to M2 then M3 ect

Yep. Totally get the use of Manual mode. But why the 1st gear only option in addition to Manual mode?