2005 Duromax Diesel GMC 2500 Mileage?

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workingtorv

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Since new this 2005 Duromax Diesel 2500 Extended Cab truck doesn't seem to get good mileage in our opinion.  Is 14 mpg gallon what we should expect from this truck, not towing anything driving mostly city?

It has 24000 Miles on it.
 
Yep.  In city driving that is what I get also.  On the open road not towing I get 20-22 depending on speed and wind.  Towing my 35' 5er and driving at 60mph I will get around 11-12 mpg.
 
kjansen said:
Yep.  In city driving that is what I get also.  On the open road not towing I get 20-22 depending on speed and wind.  Towing my 35' 5er and driving at 60mph I will get around 11-12 mpg.
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About the same as my F-250 with 6.7L diesel and it's only a couple of months old.  Cruise control sure helps with the mileage.....a lot more than in the car.
 
I have a 05 Duramax Crew Cab 4x4 with 35" tires and I get 18-19 mpg all the time. On my last trip to California I got 22. I have EFI live and exhaust. Good luck,
 
Mine has the LB7 engine, which came out in 06.  They raised the power but hurt the milage.  It's got 115,000 miles on it of which about 40,000 has been pulling our TT and another 20,000 pulling an equipment trailer.  Even when I'm not pulling the trailer, its heavy and weighs about 8400 lbs full of tools and 100 gallons of fuel.  I get around 18mpg on the hwy without the trailer and 9.5 to 11 pulling the TT depending on the wind.  The equipment trailer weighing about the same weight as the TT but much less wind resistance gets about 12 loaded.  I've kept track of every gallon its used since new and the overall is 14.1mpg.  I don't know about around town  seems like it runs around 15, however I've never checked it.

As a side, the computer mpg varies a lot from tank to tank and I don't trust it.
 
Thanks for all your responses.  I am not surprised with the variants.  Our friend has the exact same vehicle and gets better mileage than us.  I guess we have ived with it this long we will just carry on.  We were mostly curious what others were getting.
 
Sounds about right.  On our 06 I generally get around 15-16 city and high teens cruising on the highway not towing.  I have the 6-speed Allison but mine is also lifted 6" running 36" tires.  I have done a few things like EGR blockoff, PCV re-route and Banks Monster exhaust but I am not running a tuner.

When towing our enclosed race trailer to the dunes for a day trip I will get around 11-12 MPG.  The trailer weighs right at 10k pounds with the sand toys, fuel and tools loaded in it.

Mike.

 
I'd like 14 in town.  I'm lucky to get 12 with my F250 diesel.  Pulling I rarely get more than 11 and that's with a very light 7,000 trailer. 
 
Just got my 06 GMC Duramax.  I have not driven it all that much and only towed once.  I love the power and stability over my old Tundra.  I think my mileage is mid teens so far....but it came with some tires that are all terrain and a little big...not huge but I think that's hurting the MPG and it's also showing me going say 3 to 4 mph slower than I'm actually going when on the highway.  Overall I love the truck so far....wish it had a bigger gas tank...I was going to buy a Cummins with the 5.9 in a MegaCab but just could not find a decent one for the right price.  This Duramax was a great deal so I'm pretty happy.
 
BigLarry said:
Mine has the LB7 engine, which came out in 06.  They raised the power but hurt the milage.  It's got 115,000 miles on it of which about 40,000 has been pulling our TT and another 20,000 pulling an equipment trailer.  Even when I'm not pulling the trailer, its heavy and weighs about 8400 lbs full of tools and 100 gallons of fuel.  I get around 18mpg on the hwy without the trailer and 9.5 to 11 pulling the TT depending on the wind.  The equipment trailer weighing about the same weight as the TT but much less wind resistance gets about 12 loaded.  I've kept track of every gallon its used since new and the overall is 14.1mpg.  I don't know about around town  seems like it runs around 15, however I've never checked it.

As a side, the computer mpg varies a lot from tank to tank and I don't trust it.
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UHHH the LB7 was the first generation Duramax.  Followed by the LLY which was a disaster and quickly replaced with the LBZ.  At that point I gave up trying to follow the GM nomenclature for the motor
BTW never heard of a durOmax?  Did you mean Duramax???
 
2004 was the last year for the LB7.  I bought my 2004 in November of 2003 and have the LB7.  Neighbor bought his 2004 after the new year and has the LLY.  I have 147,000 on mine and he has 46,000 on his :)
 
donn said:
UHHH the LB7 was the first generation Duramax.  Followed by the LLY which was a disaster and quickly replaced with the LBZ.  At that point I gave up trying to follow the GM nomenclature for the motor
BTW never heard of a durOmax?  Did you mean Duramax???
Click to expand...

The LLY was available in two versions.  The first version (mid 2004 thru 2005 model years) did have some issues but not what I would call a disaster.  The next version LLY 2006 model was the EXACT same engine as the late 2006 thru 2007 classic body style LBZ.  The only difference between the 06 LLY and LBZ was the tune on the PCM.  The 2006 also was the first model year with the 6-speed Allison mated to the LLY then the LBZ.  Those were in my opinion probably the best built ones mainly due to the non-existant exhaust aftertreatment/DPF designs but that is personal opinion.  I looked long and hard to find an 06 for the LLY/LBZ engine with the 6-speed Allison mainly because I did not want any more emissions items on the vehicle.

Mike.
 
2011 Duramax was a whole new truck. On a 7,000 mile trip to California and back through several mountain ranges at 68 MPH most of the time pulling a 38 ft. Montana @ 15,500 lbs we got 10.2 mpg. Interestingly enough my friend has a 2012 Duramax  with a cap on it. He has a 6,000lb. Everlite which stands with a slopped front  aproximately 2 feet over the cap. Last summer we left Portland Indiana together and  at Angola New York we had both used exactly the same amount of fuel. That blew our minds but I think it all comes down to aero dynamics. The Montana front is a watered down shape of a large aircraft. The other thing I have a loovered tailgate which deflects air under the coach. Without  trailers we both get 20 mpg us gallons.
 
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