Don't feel bad. I did the same thing back in 2002. I couldn't keep a auto tranny in either of my 4x4 Dodge duallies pulling a big LQ trailer....... I love the Duramax. You will love the difference. My GMC 4x4 crewcab dually went 70K miles before it needed tires and is still on the original brakes at 95K. That Allison tranny is the next best thing since sliced bread.

We also have a Sportchassis M2 we got in 05 to pull the big trailers but if I am going anywhere that I think I may need 4WD, I leave the M2 at home and use the GMC dually. It is very capable of pulling the load. My favorite LQ trailer has electric/hydraulic brakes so that combined with the Allison makes for very good braking. Obviously not as good as the M2 would give me because there IS a big difference between the trucks.

I only have had one problem with my tranny. Since my dually is not a daily driver and sets weeks at a time without being started. We have to let the tranny fluid warm up a while in the winter before we engage the tow/haul feature or it will default to 3rd gear. Usually, about 5 to 10 minutes is sufficient. It can easily be reset just by turning it off and restarting it. Next time we need a tranny service, we are going to have them put in a colder climate rated fluid. This was never a problem when we lived in MD but after the Tranny service was done here in AR, it took a while to figure out what the heck was causing it to default.

Enjoy your Duramax, you will love it!

This is the 1st I've heard of it, although I'm sure there is more information out there somewhere in the forum. My wife really likes (prefers) the Dodge to the others we've looked at.  We're leaning towards the 2500 with the diesel... would a 2500 have the same bed height issue you had with yours? 

BTW - Good luck with the GMC - Among the 2500's I actually prefer the GM (Chevy/GMC) over the Dodge.  As a side note, I was amazed how much less expensive the Dodge's were when compared to Ford or Chevy (comparing new).

The difference at the top of the tailgate was 5" from the Dodge to this GMC. Yes the 2500's have the same problem when compared to other 2500's. I still believe the Dodge's are the best looking trucks out there, but my truck has to work and I shouldn't have to adjust anything to make it do so.

As far as the price goes I could have bought a new Dodge for far less than the GMC. Somewhere in the nieghborhood of $3,500 equally equiped trucks.

All that being said I'm starting to get used to this GMC, second full day, it's growing on me.

You may miss the power of the cummins? Trust me; it's still there and depending on the year you're comparing it to there's MORE.

The duramax was from what i understood to be the power house of the diesel gang for the last 5 years or so.

Either way, enjoy your truck, I know i just love mine! (07 Crew Cab 4x4 Sierra LT Dually). we bought a exiss 310 event living quarter trailer and there's not a hill to this day that makes me nervous :)  You'll also like the grade braking feature; after having it I cant live w/out it....

I considered this option heavily, priced more than one. Also looked at a complete air bag setup removing the rear springs completely. But if I put a flat bed on my truck and adjust the trailers down so they tow right, now I have a bunch of trailers that only I can tow. Not such a bad idea, except my mother-in-law likes to borrow a couple of them from time to time and the couplers would be to short for her truck. To late now for any of those options new GMC/Duramax in the driveway.

But if I put a flat bed on my truck and adjust the trailers down so they tow right, now I have a bunch of trailers that only I can tow.

That's generally the excuse I use for NOT lending out my stuff.  It drives my father in law nuts that I don't have (on purpose) a ball on the bumper/reciever hitch of my truck so he has to use his new truck to tow his trailer.  It's not like he doesn't have a truck, he just doesn't want to get it dirty/scratched.

BUUUwaaaaa!!

I love it that your F.I.L. does the same thing.  I just hate to be an a$$hat, but they need to use their own vehicles. ( did you ever notice the gas tank is never refilled either?) I have lite grey upholstery, and my relatives have sticky fingered kids with food, or no manners, ( read wild indians!),  in the truck all the time too. Soooo... they don't get to use my truck.

Sorry I pissed you and Al Gore off on the bedliner. Plastic bedliners have to be the dumbest thing the auto makers have ever come up with beside the grille/headlight combo on the Chevy's. $3500 well spent so far, and I aint paying nobody to adjust the hieght of a pick-up that is suposed to be built for towing.

I posted above about the truck worked fine when I had the large(14' aprrox 14,000lbs.) LQ trailer, I sold it on this site, the wheels on that trailer were towards the rear so it squatted the truck down. Now I have a 32' Fifth Wheel "only" weighs 9,800lbs and it didn't make the truck squat enough to be able to tow it, had the hitch on the trailer adjusted up as far as possible(4" from tailgate to trailer) Couldn't even park it due to small decline from the road to my drive, the tailgate hit the trailer. I had to unhook it and take the tractor and park the trailer. After measuring everything multiple times the only way the truck was going to pull that trailer was to let it run downhill, or adjust the trucks rear suspension. I did look at removing the plates under the spring stack, that would have gained 1 5/8" at the rear axle and 1 3/4" at the tailgate, that was not enough. I looked into removing the whole rear suspension($2,500) to go with an airbag 4-link type setup. That's when $3,500 for a new truck didn't look so bad. By the way when did "weenie 16" wheels" dictate the load rating, I thought load ratings were determined by the tire, not the wheel.

I did get an aftermarket exhaust brake put on after burning out my brakes in the Rockies last year.

I didn't know you could do that.  Did the dealer have to do that? What did it run, if you don't mind.....