Mine has done alright, it sits in the driveway unless it is towing.  Im not as enamored of the Allison as some people, but I dont have any real complaints about it either.  Plenty of power, although the Dmax/Ally doesnt lug like Im used to with a diesel.  Give it much loud pedal under a load and it will downshift and "scream" away.....more like a gas engine.  Took some getting used to.  Fuel mileage is what it is, better than gas but diesel still costs more. 

Pros;

G80 locker rear end is light years ahead of any limited slip offered by Ford or Dodge.  Although I still get stuck on a regular basis.

Fuel filter is easy to service.

Low to the ground, even with 4x4.

Cons;

Brakes are terrible, although they apparently last forever.

Tires are on the smallish side, perhaps why I seem to be stuck on a regular basis.

There is a steering column rattle that is fairly common and appears to have no permanent fix.  I just ignore it now.

My 2007 Dodge HD just went in for a check engine light. (I left the LQ trailer plugged in over a week and run the batteries down)  They could not fine out what happened, replaced the batteries the the CEL came on again with a transmission code, down 9 day waiting on parts for the new 6 speed auto trans part.  Was told that the drain on the batteries caused a surg in the electrical going to the trans.

WOW, too much computer crap for me.

Still love it, hate the mileage but cna't find nothing else to carry the weight without going to a larger truck. 

Like the ride of the GM, but the rear spring just want hold the trailer up and the brakes will not stop it.

We had a 2001 Duramax. Loved the quick pick-up at a stop light - was fun to leave the Beemers in the dust!

Down side - the fuel injectors were a constant problem. Chevy recalled them and fixed them for us twice. The third time we traded it in.

At the time we were just pulling a 4 1/2 short wall LQ - 3 horse. Anything bigger and we would have had to add helper springs.

I miss driving it, but hubby says I can't have another sport truck. :( Something to do with tickets.

2001!

The first couple of years injectors was a big problem in the d max, but GM did step up and offered to fix the problem even on 100+-k mile trucks.

Yes, we also had one of those and the injectors went TWICE!!!  The problem was not GM not fixing it.  The problem was waiting to get them as they were so backlogged!  We traded on the second round. 

Bought '05 4x4 Dmax in '06. Have 70k on this one and this is our 3rd one. Absolutely no problems on any of them. Did put in the Edge chip, 5" exhaust, KN air filters, etc and that did increase the mileage and power. Gets 18 by itself (wife gets 20) and 11 pulling 19k LQ trailer. Has a Hauler steel bed on it so has more than enough weight on it. When I trade, plan on getting another just like it.

I have an '04 Duramax whose sole function in life is to pull my trailer.  It does a great job and I love it (this coming from a former die hard Ford person).  I have absolutly no frills on this truck, regular cab, rubber mats, manual locks, manual windows, manual mirrors (which can be a pain).  I have a small SUV as my everyday vehicle because I figure it is cheaper to replace the SUV than a decent hauling vehicle.

Chad, the fix to the permanent rattle in the steering column is to install a better stereo....

I've got an 05 Duramax. It's the 3500 Extended cab dually. I LOVE this truck. I did add taller tires to it though. I have replaced my breaks one time. It has 127,000+ miles on it. It not only pulls my trailer, but is my every day driver as well!!! I have not once had any "soundness" issues with this truck. My only regret is not getting a crew cab. I could use that extra room!!! I did change out my mirrors for the vertical towing mirrors.

I believe you may be right.  I tried just turning the stereo up (I dont have the Bose) but then I had a rattle AND lousy sound coming from the speakers...........

I now have a squeeky sound coming from the driver's side dash . It does this at about 45 mph and higher. What's up with that? We rotated the tires thinking maybe......wishful thinking. I then thought maybe the hood needs adjustment.......Not......The front end was checked over and nothing was found.

I knew there would be some quirk to offset the low miles perk.  

I pulled our boat home (#8000) from storage and oh my, what a beautiful effortlessly tow..........I have to admit, the triaxle helps. What a motor. It felt like it was slowing me down on it's own. Bare with me, I am a first time diesel owner.  I can't wait to pull a gooseneck....