improving mpg while towing

rambler82rambler82 Member Posts: 3
edited June 2014 in Chevrolet
I recently bought a '09 duramax 3500 for towing a cargo trailer. I am very disappointed that I only get 9 mpg while towing! Any ideas on the best way to improve that? Every thing is factory stock.


  • catamcatam Member Posts: 331
    How big and heavy is your cargo trailer, and how fast are you driving while towing?

    Those are the biggest factors for economy while towing.

    I have an 09 2500 Duramax, I average 11-12 MPG towing a tripple rig of boat and pop up trailer ~8500#. I never go faster than 70 towing the tripple setup for safety reasons.

    I have on 2 occasions just towed the boat ~6500# , and drove 75 -80 MPH, my mileage dropped to 10.3 MPG, even with less weight.
  • rambler82rambler82 Member Posts: 3
    Sorry I didn't respond sooner! The 5th wheel cargo trailer I tow weighs around 10,000# give or take. I do alot of back roads which I'm sure zaps the mileage. Some highway driving at 65. I don't wan't to mess with factory waranty. Any ideas how to improve mpg or should I just live with it? Thanks
  • catamcatam Member Posts: 331
    I agree with not messing with warranty for fuel mileage.
    From all the research I've done, there is NO "chip" out there that has proven to improve mileage while towing. Certainly not enough to even pay for the chip not to mention the warranty loss.

    As far as how you are driving, yes the backroads will zap the mileage, just think of the idea that you are ~ 17,000 # GCVW, everytime you tap the brakes for a 45mph curve you waste energy, and then have to accelerate that mass you use extra fuel. Even worse when you have to stop at stop signs in small towns.
    I assume your "cargo trailer" 5th is significantly tallet than the truck. so you are also being punished by aerodynamics.

    Only other thing to mention is your Allison tranny. Your best bet is to put it in drive with "tow/haul" on and go. This tranny is designed to tow in 5th and 6th gear which are both overdrive gears. The tranny programming works very well, the more ofetn you are towing in 6th gear the better your overall economy will likely be.

    Other than that you are probably going to have to accept the mileage.
    Look at the bright side, though, I can't think of another vehicle that would tow it and provide any better mileage, and with the Dmax you have enough power thatyou don't have to worry about hills or anything else. Good luck
  • rambler82rambler82 Member Posts: 3
    Thanks for the input. You make some good points. I do leave my "tow" buttom on while pulling my 5th wheel. I hate that I have to re-apply it whenever I restart the engine. I am getting used to that now. I am coming to accept the mileage. Thanks again
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