Duramax MPG

Discussion in 'Trucks and Trailers' started by 6'7 330, Aug 21, 2005.

  1. 6'7 330

    6'7 330 LawnSite Bronze Member
    Messages: 1,821

    I would like to compare notes, with other landscapers with Duramax diesels, on what kind of mpg you’re getting.

    O5 3500 six speed - 14.5.

    O5 3500 with Allison - crummy 10.5

    02 2500 pickup with Allison 13.0

    UNISCAPER LawnSite Bronze Member
    Messages: 1,426

    From one Bill to another, this one having lived in Chicago, and having Duramax trucks hello!

    Let me ask how many miles on your trucks first? Here is what I noticed...Now, fisrt, our region has some of the steepest slopes the country offers being in the foothills of the Sierra Nevada Mountain range, and, our freeways offer lots of 90MPH traveling.

    When every Duramax we had was new, milage ranged from 10-12 on a 3500 4x4/allison to 13-14. We keep highway speeds around 70, unless it is early befor traffic hits.
    After 10K, things really loosened up. I took a trip to La to get a certification, put on 500 flat highway miles. Speeds ranged from 70-75, to the short run off the freeway to where I was going. We hit between 17 and 18.

    Around town, pulling a trailer with a Cat MTL, (12,000 lbs) we get between 12 and 14. I install K&N filters on every truck we own, because they will get you another mile almost in every applcation and provide better filtration overall, with the ability to clean and reuse the filter.

    In the 4500, 5500 series, we originally got 9MPG, right about what the Ford 7.3 PSD's were getting after 10,000 miles. Now we are aproaching the 19K mark on one, and the 33K mark on another. both trucks, loaded or empty, running 11-12MPG with allisons, but lets keep in mind they are running highway 99% of the time.

    These numbers seem fairly consistent with other Duramax owners who run our same areas, while Ford owners are hitting well below that, except those who run the dial a horsepower superchip. Then, if they keep their foot out of it, the milage comps out close. But as soon as they run with the foot to the wood, milage goes below 9.

    All in all, I can accept the milage when you consider the trucks are never down for anything other than PM. Time will tell the true tale here, and I have a projected replacement life of 500K on each unit, unless we see the need to make changes prematurely.
  3. 6'7 330

    6'7 330 LawnSite Bronze Member
    Messages: 1,821

    Hello to you to Bill!

    The 02 has over 60k miles.
    The six speed 05 has just at 10k
    The allison has around 5k

    UNISCAPER LawnSite Bronze Member
    Messages: 1,426


    Let me pass this one along to you.... Have you gotten the 30K check ups as recommended? They typically will run $650.00 with labor, parts and so fourth. What they do....blast out all the imperfections in the fuel that clog injectors and change your timing. They typically will boost milage until the next round when injectors get clogged with the crappy fuel we all have.

    I guess the next question is how much weight are you loading, and what is your driving condition? If you get stuck in that Hillside strangler or expressway traffic, or traffic on the feeder streets in Chi town, I can see how easily your milage would drop. Have you tried comparing to anyone else in your immediate area with a similar truck and situation as you? That is typically my gauge. Coast to coast won't tell you much because the circumstances are different everywhere. Though your slopes and hills are not even what I call hills after living here, the traffic start/stop thing really puts the screws to milage...
  5. Mowingman

    Mowingman LawnSite Platinum Member
    from Texas
    Messages: 4,714

    A good friend of mine hauls new cars all across the midwest for a local Chevy dealer. These are cars being transfered from one dealer to another. He uses a dealership truck, a 2500 with Duramax and auto trans. He says the fuel mileage is terrible, wheather the trailer is loaded with a car, or empty. Ave. for pulling empty trailer is 13MPG. Average for pulling a load drops to 9 or 10 MPG. He has his own Dodge 2500/Cummins, and gets 13-14MPG all day long with a large slide-in camper on it.
    The Duramax may be a good engine, but it sucks fuel, from all reports I have heard.
  6. 6'7 330

    6'7 330 LawnSite Bronze Member
    Messages: 1,821

    All the trucks are maintained well. They are towing 16 foot trailers, loaded with two lazer z mowers, Two cycle equipment, roughly 4000lbs.They go out on the suburban route, traffic varies from stop and go to light , always heavy in the evening on the way back to the shop.

    Good point, about comparing figures from different parts of the country, areas can have very different variances.
  7. Travis Followell

    Travis Followell LawnSite Silver Member
    from KY
    Messages: 2,206

    Do you pull in overdrive with the Allison's? If not that would make them burn more fuel because their turning more rpm's. We only turn o/d off when we pull heavy loads with ours Duramax/Allison.
  8. HandEnterprises

    HandEnterprises LawnSite Member
    Messages: 23

    i have a 2005 gmc k2500 crew cab long bed allison. i have tracked my mileage since new(it now has 5200 miles). no load, open road driving 50-65 mph i get almost 21 mpg. loaded with 16' trailer(two scag hydros and one lazer or three hydros) and two cycle equipment and a **** load of grass in the bed, open road i get 15-17 mpg. loaded same as above in town(stop and start) residential route 13 mpg is the worst i have gotten. before i bought my truck i asked everyone i saw with one what kind of mpg they got and i heard good and bad, everything from 9 to 28(28 my ass). there was a wide range in the three trucks that we test drove. the chevy crew cab dually only got 13 mpg with or without the trailer( had this truck for 24 hours 150 miles ). the next was a chevy k 2500 crew cab short bed, 15 mpg mixed( 20% city 80% hiway) we did not tow with this truck. all three trucks were four wheel drive and loaded.
    i have had my gmc for 5 weeks tomorrow and have no complaints.
  9. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Messages: 2,613

    UNISCAPER, I have read numerous reports on the TDR (turbo diesel register) regarding how K&N filters perform very poorly compared to an AFE setup or stock paper element. IMO, after seeing the numbers from a controlled air filter study on the diesel stop, get that K&N off of there. http://www.afefilters.com/ is the url for afe, not wanting to spur an arguement but informing you that there are much better airflow systems than K&N.
  10. Albemarle Lawn

    Albemarle Lawn LawnSite Bronze Member
    Messages: 1,544

    10 mph highway tops if you baby it.

    Around town maybe 6-8 mpg.

    Has an attic over the cab, usually loaded to about 19,000 lbs.

    This truck is a fuel pig. I feel like I'm funding terrorists every time I turn the key and have only logged 8,000 carefully planned miles.

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