Hey guys, I just got an 08 GMC 2500HD with 6.0l Gas engine, and I love the truck... but after picking up my new trailer I'm considering trading it in after 3 months of owning to get a diesel. I've searched and read a lot of threads about MPG but everything really talks about unloaded. When I got the trailer in Oregon towing back I got about 10mpg with it unloaded at about 6000lbs, I thought this would be acceptable. But after loading it race ready at about 12,000lbs I got 8mpg according to the DIC which won't work for me. Can you guys post what kind of MPG you are getting with what kind of loads over long hauls... this might determine whether I spend all this extra $$$ and take a loss, or just live with the truck and the mpg it currently gets. PS: I only have 4000miles on the truck and I know with more miles the trucks seem to get better mileage... atleast my 05HD did.

All input would be greatly appreciated

thanks!!

I've never pulled a car trailer with a 6.0L, but my '88 (454 ci) would get around 9-10 mpg, pulling my old enclosed car trailer (9K pounds on average). And, my '95 7.4L would get around 11-12 mpg pulling the same trailer on the freeway.

My wife's Yukon Denali (6.0L Vortec) gets about 12 mpg pulling the horse trailer (fully laden about 5.5K pounds) on the freeway.

Now, my LBZ gets about 14 mpg pulling my current race car trailer on the freeway. Average weight for my trailer is about 14K pounds fully laden.

I had the 03 Chevy 2500HD 6.0 gas and had the same problem. I bought the truck and then decided to buy an 11K 5th wheel. The truck was rated to tow 10K if I remember right so I was over weight to begin with. The milage was a killer and towing in the hills was not good either. I had the truck 1.5 years and then traded and took a good hit at trade-in but was worth it for me. Now you have 4000 miles and will take a huge hit and the 2500HD gas trucks are worthless at trade-in value compared to diesel so try to see what they will do for you at the dealer. On mine, Dodge gave me more for my 03 Chevy then the GM dealers so that's one of the reasons I'm drivng Dodge. I would see what you can get and then decide. Good Luck

Oh I forgot about the milage but with the diesel you should get 10-13 towing I would think.

I got about 10 with mine towing 75-80 mph up mountains

I only get 9 to 10 towing with my diesel. And that is on pretty flat gorund. I haven't towed in the mountains yet. My trailer weighs about 8k. If I were you, I would probably stick with what you have. You would have to tow a lot of miles to make up for what you would lose in the trade plus the added cost of the diesel.

Thanks for the input, keep 'em coming guys!! I totally understand the stick with what I have concept, but the towing I do is gonna frustrate the hell out of me knowing I'm sitting in 5th gear going 65 knowing I can't touch the gas or I'm down to 7mpg... and with 25 gallons that makes for frequent fillups on long hauls which I plan on doing. I think that for the peace of mind, and MPG/Balls at tow-time will be worth it if I can get what I need to get out of mine to make it happen. Only reason I'm thinking about doing is because I have a GM Supplier discount that gives me $2500 rebate, supplier price of straight invoice, and whatever GM rebates are in effect which would be 1k, so invoice and 3500 off isn't a bad deal if I can get 30 for mine.

Vin nice nova in the icon, is that yours.? I have a blown alky 70 chevelle doorslammer

Diesel will pull much nicer but keep in mind, when I looked at one Shell stations price today it was almost 3.50 a gallon.

Diesel will pull much nicer but keep in mind, when I looked at one Shell stations price today it was almost 3.50 a gallon.


:jawdrop: I would be HAPPY to pay 3.50 a gallon for diesel (if I owned one) but here in the bay area, things run a little bit high... :jawdrop:

Keep in mind that the Duramax/Allison option runs close to $8000. Don't get me wrong the diesel is unbeatable for towing but with the higher diesel fuel costs and maybe 4 to 8 MPG better its going to take a LOT of miles to see a return on your investment.

I got An 05 3500 GMC single rear wheel with a 6 litre engine dont really know what kinda milage i get in it dont have that info on the dash but i use it for landscaping and snowplowing lots of power, but it always seems like im at the gas station with it. I cant complain about it when i am plowing i get about 18 to 20 hours on a tank but just driving around it seems to drink it faster then i can put it in. I just got a 2008 CC Dually last week with a Duramax got about 800 miles on it most of that is plowing i am getting 8.9 miles to the gallon i know it wiil come up once i start getting on the highway with it but so far i am happy with it.

Oh by the way here in southern Ontario diesel is running about 3.97 a US gallon and gas is around 3.85 a gallon.

Gas....2.82

How many times a year are you towing ? If your only towing 10 to 15 times a year keep what you have.

I get about 12-14 MPG pulling my car style trailer, depending on conditions. It probably isn't much over 5000 lbs fully loaded though.

i had 03 gmc diesel got 16 in town 19 on road towing 36 ft. 5th wheel got 13 got the fever and got a new 08 king ranch it was pretty, but had it 6 months 20,000 miles 14.8 at 65 at 75 13,8 flat ground 11 to 9.8 in town
towing at 65 7.5 so no a happy camper got a 08 lmm every happy cost me 7500.00 to trade but the first day i save 30.00 in diesel on a run i make all the time about 350 miles next day working stop and going about 150 miles
15.00 in diesel. i had the lmm 3 months 5500 miles added ppe love it and
have not look back oh yes it get about 16 town 18.5 at 75, and 3 times
the power, my 2 cent worth

harley

I got 12 miles a gallon pulling my 7000 pounds of trailer up Cajon Pass and Baker Grade to Vegas and back a month ago. Never even had to take it out of cruise! :)

I see about 10-11 pulling the trailer seen to the left <------

Well I went out to the dealer and drove a couple diesels and was pretty happy overall... on the way there I set the cruise at 70 in my gas and reset the avg econ on the DIC and got about 17mpg instant... did the same, the 4x4 pulled about 15.5, and the 2wd I was looking to get was up at 19/20 over 4 miles of flat road.

Get back to try to work a deal and these theives want to give me 24k on my 2 month old truck!!! They wouldln't go much higher.. I was looking to get closer to 30 to make it happen, but they weren't even close. So I just told them, thanks but no thanks and took off.

Oh well.... wish it would have worked out, there's still the chance a private party will pick it up with all the ad's I have out.


anybody wanna buy an 08 GMC? :)

someone on here is selling their new LMM due to starting a new business. You might want to ask around. That person didn't know where to post it. Look in the section below the new comers and I beleive the title to his thread was Red Dog or something like that. Good Luck!

I have a 07.7 Lmm Crewcab fatback and have towed a Trailer for most of its 25000 miles. On average pulling my work equiptment trailer at 75-80 on flat land or threw mountains I get 10.5 to 11.5 and the trailer is 12,000 lbs. Pulling my 30 ft 5th wheel which is 9000 lbs I got about 13mpg at 75 mph and 14.5mpg at 65... Hope this helps!!!! Also towing with this truck is a dream...towing threw the mountains I think it only downshifted once....hows that for POWER!
And for the record with a PPE tune#2(90HP) I get 19.2 at 65mph.....and about 15.5 AT 80!

Remember also, that the LMM option goes from $8000 to $5900 at invoice price! This makes the upgrade a little easier. Add in some GM perks or incentives and it's not all that bad.

K

The LMM is mine!! if I can only sell my gasser... if not, I guess I'll just live with it

Ho Ho Ho to me for not getting the diesel to begin with :(

Dude ... hard core!

Back in 2003 I bought a Sierra 1500 w/quadrasteer, while thinking I really wanted the diesel. I drove it for 35,000 miles with zero regrets. But I went out and bought the diesel after 4 years. You did after 4 months~!

My horsetrailer at about 12k pounds AVERAGE I would say is 10 mpg, I've seen as high as 14 mpg but it's been very rare. California's towing laws are 55 mph but i'm usually cruise control on at 62 mph. That's pulling some hills and mostly flat.

EDIT: that's completely stock and UNtuned.

Well Jason looks like we can agree we are not B.Sing about millage...sounds like we are pretty close.....I am saying I get the same in hills or flat within .5mpg anyways....I'd say that is pretty good!

Well Jason looks like we can agree we are not B.Sing about millage...sounds like we are pretty close.....I am saying I get the same in hills or flat within .5mpg anyways....I'd say that is pretty good!
Yeah within .5 would be a good guesstimate between hill pulling and flats difference. It's funny also If I'm FAST and hard up a hill it seems to take less fuel than if i pull to the side in the slow lane and not use alot of power...
I think it's good, 12k is alot of weight being yanked around by a truck that weighs 8k pounds empty by itself.

I stay in the fast lane and go 75 or so LOL.....I pullled threw the Applacation mountains about 4 times and had it kickdown probally a total of 4 times....the engine is amazing and torque is unbelievable...and that was before the I added the ppe tune

Keep the truck you have!!!! As I did exactly what you are contemplating. It has been a total let down. Unless I just got a lemon, I get about the same mileage. More power yes better economy not much if any & if any thing it gets worse mileage now at 3K than when new.

Agreed ... mileage on my LMM seems to be declining slightly as miles accumulate, from zero to 3,000. My guess is that the DPF is gradually accumulating crud.

However, can't agree on the rest. My Sierra half-ton, with quadrasteer, is a terrific ride. But it's no comparison to the power of the LMM. Further, even with the LMM's gradually erosion of economy, it's way better than the average 12-city that my 5.3 L can achieve. Averaging 13 to 14 in pure city shuttles, the Duramax power more than compensates, IMO. Besides that, whenever I'm on a roadtrip, it easily reaches 18 mpg, whereas the gasser was hard-pressed to reach 16 mpg.

Well I disagee with newtodisels...... you will not regret it and I have 25000 miles on my LMM and the milage got better after 8000.....my gaser when puilling the same weight got 5 maybe 6 mpg..... and in the hills I had to pay alot more attention to the shifting and size of the hill.... the LMM DOES NOT CARE......I can go up a steep grade and most of the time not even realize that I did!..... This is my first diesel and I will never go back!

No question it tows with much less effort! However, towing around 10K I can't top 8MPG. Just recently went on a short road trip unloaded only got 13. I only average to & from work 12ish. My frustration is that my '07.5 6.0 with 4.10's seemed to do better except when towing which isn't often.

How many miles and what sort of city/Hwy service mix?

It's just a hunch, but I'm wondering if the LMMs getting really poor mileage are just not getting enough highway miles. If so, the DPF could be getting unexpectedly loaded up. These are the first examples of this NEW TECHNOLOGY, so they're likely to suffer some growing pains. Sorta like Bill Gates using his mainline customer base as Beta testers.

That's what we are . . . DPF Beta testers!~! :badidea:

Maybe you have a issue with your truck.....hookedondiesel and I get the same towing 12000lbs and I am towing that at 75mph min and I average 10.5 to 11.5

I made my first real pull a month ago with about 8000 miles on the speedo, pulling a 8000# 26' boat thru hills at 75mph I was getting 8 to 9 mpg I'll be pulling the same boat again in the morning on flat ground at a much slower pace and hopefully it will be a lot better.

going boating on christmas..WOW that would be quite a stretch for me. have fun!

Friend of mine removed all the smog shit on his new LMM and gained 3mpg with under 5k on the motor and he drives fast. I test drove a new 6.4 f350 dually and not towing it said 4.5 and when I got on the freeway and reset it at 65 it was showing 7.5 mpg. I bet the dodge is sucking the disel to with all that smog shit corking it up.

I almost wish something is wrong, then once corrected the Mileage would go up. I just don't know what it would be, as it runs fine & hasn't thrown any codes in the last 1500 miles. It just pains me to have to spend $1000 bucks to delete the DPF & void my warranty.

yeah ISRACING I hear ya....I get 9-10 mpg w/an '03 HD2500 Crew 6.6TD towing a 9800 lb travel trailer....but 17-19 regular driving. Before I got the Duramax towed the same trailer w/an 03 GMC1500HD Crew 6.0L gas & an 06 GMC 1500 Crew w/a 5.3L gas ALL STILL getting that magic # 9-10 MPG. I've about all given up on the fuel milage while towing & happy w/the Diesel power I get (still all stock). The way I fixed the MPG is I added an external fuel cell 60 gal cause 26 gal stock tank doesn't cut it (RDS tank /tool box combo that gravity feeds into main tank.....no switches ect) Now I'll fill up after GW Bridge in NJ & drive w/trailer to exit 181 in SC, not bad in my book. :D

I've got an '02 D/A with a Hypertech on level 2 and 265-75's. Pure highway @ 75-80 = 19mpg. Short trips around town = 14mpg. Towing a 29' 5'er @ 8000# = 10.5-11.5mpg. Towing a 39' 16500# (CAT Scale) toyhauler on highways, flat or the Smokey Mts. = 8.3-8.9mpg but the power is awesome. I had a Z71 with the 5.3 and unloaded mileage was no better.
I'm also looking at an '08 dually LMM and I hope it's mileage/performance is similar to my LB7. I think the power outweighs the mileage. Just set the cruise and go, DMAX!

I get between 13 and 15 driving around town. 16 to 18 when mostly freeway driving (that is SoCal freeways). 9 to 11 when towing a 15K plus 5W toy hauler. All stock with the exception of Pirelli Scorpions.

I had an 05 2500HD gasser and it would get 14 on the highway and towing a small enclosed trailer it would get 9. Sold it and bought my first diesel which gets 20 on the highway and gets 14 towing the same trailer as I did with the gasser. I will never by another gas truck in my life. The power difference and ease of towing is more than a person can imagine. Sell your gasser and get the diesel!

Keep the gasser,you'll be way ahead by the time its paid off. the difference in trade between a gasser and diesel is only about half as soon as you leave the lot. the only item that actually holds value is 4wd over 2wd. and if you tow alot put a lot of miles on it repairs out of warranty are gonna be more costly on a diesel.

I have a 2007 2500HD Diesel and pull a 30ft gooseneck horsetrailer with LQ. When fully loaded with 3 horses, tack, etc... it weighs in around 14.5K. I pull at about 65 - 70 MPH and get between 13 - 14 MPG. But that's in Indiana where everything is flat. My 2006 2500HD pulling the same trailer got around 15-16 MPG. My dealer explained the differnce due to the way the 2007 is tuned for the low sulfer diesel fuel.