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Random Quote: Give a man a fish and you feed him for a day. Teach a man to fish and you get rid of him on the weekend.
I'm getting ready to place my order for a 2006 2500HD w/ a Duramax and wanted to see what kind of fuel economy other Duramax owners are getting when pulling a load and without a load.
I have a 2005 Duramax crew cab w/13,000 miles on it. I pull a 23' Grady Gulfstream with a hard top that has a 24" radome on top and an electronics box hanging from the hard top ceiling (more wind drag). I have twin 175 Evinrudes. I get about 9 mpg pulling the boat at 65 mph. With no boat I get about 17 - 19 with a combination of city/hiway. I don't have a chip or programer on the motor. Make sure your tires are pumped up to their max rated pressure. Your economy will improve slightly. The above numbers are with a tire pressure of 65 - 70 psi. The tires are rated for 80 psi but at that pressure and no load the truck rides too stiff for me.
I thought I would get better mileage but the truck rides and handles very well while towing on the highway and in the city. The more load you put on it the better it rides. The extra torque of the diesel really makes a difference. I hope this helps.
My boss has a gmc 2500 w/ the duramax and gets 18+ empty .We have a excavator that weighs w/ trailer 10,200 on the scales and that knocks his economy down to about 12 or 13. I've got to say it's one sweet truck with a very reliable engine and with that tranny you just can't go wrong with that package. I'm looking to upgrade to a 2500 and sure wish I could afford the 6000 dollar option that the duramax/allison combo runs but I don't know that it's in the cards for me. I drive an international 4900 for the guy and he'll leave me in his dust when I'm driving with no load and he's got the tractor hooked up to his truck. I think you'll be very pleased with it once you get it!
I have a 2004 Duramax/Allison. It's a great combo. I haven't towed with it yet, but I have been able to get 22 mpg unladen while driving in New Mexico at 55 mph. Driving 65mph, I usually get 21mph unladen, and if I go any faster, the mpg drops. All of these figures are highway only.
We have a 2003 GMC Duramax with the Allison. When pulling a 21.5' fifth wheel and 19' cuddy cabin boat, got about 12 mpg the last two years. Have only pulled our new Sea Hunt Escape 220 four times, but appears that we are getting around 12 mpg driving 70 mph. I get about 14 around town in the summer months and drops to about 13 in the winter. Have been very pleased with the package since we have owned it and have put a little over 45,000 in a little less than three years.
__________________ jal
2009 Crestliner Superhawk 1900
175 Optimax Pro SX
Dodge Ram 2500 HD Cummins Diesel
I also have a 2004.5.I have just a little over 5K miles I pull a Grady Seafarer 228 HT radar.I figure about 20% of my total milage has been towing and the milage computer says 15.8 average MPG.Like stated above I`m probably gettin 17/19 with out the boat.You will really like the way that drive train works with a load on it.
I'm running a 2004.5 Crew cab short box 2500 HD Duramax/Allison. She's got 35000 miles under her belt and averages 20 mpg @ 70 mph unloaded and 15 mpg pulling ~6500 lbs of boat @ 65 mph.
Thank you for the replies. Are there any options or features you wish you would have added or deleted now that you've had your trucks for a while? Also, how is the leg/sitting room for the rear passengers? I have 1500 series now and it's tight trying to fit two adults back there.
The crew cab is like the first 2 rows of a Suburban. There is plenty of body and leg room for 4 big guys.
The only thing I wish I had added as an option are the big towing mirrors. The standard ones look good but don't stick out far enough for me to see the back corner of the boat when backing into my parking spot at the house. I have to hang out the door to keep from running over the hedges.
I have 03 chevy crew cab with duramax I just got done with a trip from New York to the Outerbanks was over 500 miles down there plus I did about 45 miles of local driving before I fueled up. I agot 18.6 miles to the gallon and that was running at night with my foot on the pedal pretty good.On the way home I traveled during the day and with traffic I was forced to drive a little slower and got 20.5 to the gallon
I have a 2005 extended cab 2500 Duramax with the allison transmission. Not sure how all these people are getting such good mileage. At 2000 miles on the truck, I am getting 15.3 in the city and 14.1 towing a 23 foot boat. My buddy bought the 4 door version and gets worse gas mileage than I do.
It is by far the worst riding truck I have ever owned. Have had the tires balanced 4 times since new and several replaced and it still rides like a bucking bronco at less than 50 mph.
A lot of people complain about the ride of 3/4 ton trucks. That's because they are running them empty and probably don't need such a heavy truck most of the time. I have a 2500 work truck with utility bed and lots of tools and gross around 7,200lbs, but the truck really rides well with another 500 to 750 lbs. in the bed. If you buy a truck rated at 8600 or 9500 lbs. GVW, and run it empty, you can't expect a good ride.
Also, these trucks come from the factory with cheap tires with very stiff sidewalls to achieve high load ratings. When my original tires wore out, I installed Michelins, which have the same load rating, but seem much softer.
Nothing much to add..... I can ring out 20 to 21 mpg empty and going 55. Pulling 8000 to 9000 lbs I get 12. Over the last 100 gallons or so of diesel I've averaged 15 mpg with the driving and towing I do......
MAXILLA I'd say 10 is good at 80. Try towing that much weight with a gas burner and see how<6 is. I towed my 228 grady on flat ground going across flat Fla. at 75 and was getting 7.2mph in my tahoe. Came back up to ATL in the rain and could only average 63 or 64 MPH and that got my economy all the was up to 10.2. If you slowed that truck down to 60 you'd see 14 or 15 probably so towing your boat at 80mph I'd say your doing pretty darn good!
fairgame - 8/3/2005 9:59 AM At 2000 miles on the truck, I am getting 15.3 in the city and 14.1 towing a 23 foot boat.
Give it some time. That engine is still wiping the sleep out of it's eyes. I'd be surprised if you didn't start seeing good improvement in mileage @ 5000 miles*and close to 20 mpg @ 10000 miles.
I will be impressed if it gets up around 20 mpg. I like the truck and it pulls the boat great. The people and the tire place don't like me much. I havent got the tool box in and started adding weight of additional items, maybe that will help the ride a little bit. I put the 265 Goodyear Wranglers on it with the medium AT tread.
I had a 2001 2X4 extended cab short bed, this truck got 18-19mpg empty and 14 pulling my 23 at higher speeds. My new 2005 4X4 extended cab short bed gets 14-15 mpg empty and 11-12 puling the same boat at speed. On some of the diesel forms (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi) there is a lot of talk about the LLY getting less mileage than the LB7 version of the Duramax. I love the power and feel of the truck, hence the 2nd one. I also recommend changing the tires as soon as you can. I just put the new Goodyear silent/strong Wranglers.
GMC 2500HD w/ Duramax 
