2011 gmc sierra 2500hd

[dshouston]

i purchased a 2011 gmc sierra 2500hd with a duramax diesel about a month ago. i haven't towed with it yet but on a recent trip solo i am getting 20 plus mpg on the highway at 70. i'm also impressed with how smooth and quiet this truck is. my first long trip towing will be to the east coast in about 6 weeks. can't wait to see how it does!

[Silvertwinkie]

Nice truck. Can you comment on the new emission control system they placed on these trucks. It seems there is now some sort of fluid that requires changing?! I saw one of these trucks a few weeks ago and of course being a vehicle junkie, took a peek underneath. Read some very basic stuff about it, but am interested in how this is suppose to work. It would seem that from an MPG standpoint, it's not hurting it all that bad.

[Pat Conway]

We have a 2007 GmC Duramax which now has 38000 miles. We pull a 1988 25ft A/S TT with it. Would hate to go back to towing with the 1999 Suburban 1500 we previously had (granted it was getting tired approaching 100K). The power with the Duramax and the versatility of the Allison transmission is very satisfying. With cruise control activated it just keeps on pulling. Mountainous terrain/uphill merger no problem. Your going to love it! Pat

[Mikethefixit]

I don't own a GMC but I like the sound of that Duramax engine. I would just venture a guess,that IF (big word) you slow down to about 60 to 62 ,keep your toe nails off the fan,in other words be patient,let the diesel do its thing(making power and torque) and sit back and enjoy the ride and the scenery you should be at about 16 to 17 mpg when towing.
Dont be disappointed if its only 14 or 15 mpg to begin with, Diesel engines take some time to actually break in. Our 7.3 Harvester did not begin to get mileage until it passed about 60 k miles.
Be patient,keep it serviced and it will reward you with many years of good service. Our F350 is now 9 yrs old and I have only replaced a water pump and brakes and batteries.
GOOD LUCK
Roger

[deauxrite]

My 2005 (diesel) pulls like a dream. The mileage is not that great, but it is smooth and strong. That is the good news...the front axles have both been problematic (replaced) as have the rear axle seals. The speedometer and dash package was recalled after two years of haggling with GM. The truck squeaks like a mouse and I grease it three times a year. It has a 26 gallon fuel tank, which is too small for towing (especially to Alaska). The interior trim is coming loose in several places even though I keep repairing and replacing. In short, a 6 year old $43,000 vehicle with 100,000 miles on it should be holding up better that this. I am finished with Government Motors..my next one will be a Ford. If it isn't better than the GM, maybe I will get a mule team..in fact if the price of diesel keeps going up, we may have to get a mule team!

[dshouston]

this truck does take what gm calls diesel exhuast fluid (def), to improve emissions. there is a 6 gallon tank that needs to be filled aproximately every 5000 miles or about at every oil change. the 2500hd's also come standard with a 36 gallon fuel tank, even with a 6 1/2 foot box, so range should not be an issue anymore.

[JBinKC]

And I would say GM's 100,000 mile warranty is tops in the industry.

[SteveH]

Originally Posted by Mikethefixit

I don't own a GMC but I like the sound of that Duramax engine. I would just venture a guess,that IF (big word) you slow down to about 60 to 62 ,keep your toe nails off the fan,in other words be patient,let the diesel do its thing(making power and torque) and sit back and enjoy the ride and the scenery you should be at about 16 to 17 mpg when towing.

We have an '08 GMC with the Duramax/Alison drive train, and on our recent 14K+ mile trip to Alaska, we averaged over the entire trip 12.47 MPG. This was driving 65 whenever the road conditions permitted.

I tried driving 55 for a couple of tanks of fuel, and the mileage was no better. I found the transmission, when in tow/haul mode, will not shift into 6th gear until about 62 MPH. The truck now has 72K miles on it.

Just my experience.

[r carl]

And GMs 4L80 and Allison tranys are tops among pickups for towing. Considered bullet-proof.

[AirsDream]

Yeah, I think you'll like it. My GMC diesel's an '08, and I get usually a tad over 20mpg with mine, solo, x-way, at 70 or a little over. Towing, I average about 12.5-13, with my best trip towing at 15.9 over 500 miles, when I wasn't in a hurry and had a slight tailwind most of the way! Slowing down a little helps a little, but max torque comes in at around 65 mph in top gear with the Allison, and that seems to be near max efficiency for this engine. I'm also towing only a little 23' Safari, so the truck hardly knows or cares it's there. I've only got about 35k miles on mine, and my previous diesel experience tells me that it'll keep getting better until perhaps 60k miles, when it ought to be fully worn in.

[BillTex]

We just got back from an 800 mile weekend; with porta-bote on the roof of the truck, bikes on the front hitch, full H2o, and 4-5 hours 4wd down some logging roads, we avaeraged 14mpg for the entire trip. This includes towing (700 miles), idling when necessary, and the off road miles. OBD was not re-set for the entire trip, and all tanks were verified via manual calculations.
2 1/2 tanks, $117 dollars in fuel. Payed from $2.45 in Pittsburg NH to $2.98/gal here at home.
With all the crap we had hanging on the roof and front bumper, I was totally impressed with this mileage, we were not exactly aero-dynamic going down the road. We had about 1000# on the truck before I even dropped the hitch on (boats, bikes, wood, ob motor, genny...) absolutely impressive efficiency.
I think you will love the 2011 deezul...
Good choice...good luck.

Bill