Gary,
Here is a link to a Ford Forum that is pretty active, there are some issues but all the makes have some;
http://forums.thedieselstop.com/ubbthreads/postlist.php?Cat=0&Board=2003Drivetrain1
I am also in the market for a new truck. Here's what I have found. Some of this is net rumor so take it with a grain of salt.
I don't have a lot of info on the GM products, for no logical reason. I did drive one the other day and really liked their Allison transmission.
Ford and Dodge are both coming out with a new engines soon, so if you want a known engine better do something soon. After Jan 07 new fed emissions go into effect on new trucks built after that date. The new trucks HAVE to burn low the new sulfur fuel. And they are going to have all kinds of new emission hardware on them.
If you want the best engine get the Cummins. That is Dodges strong point. I have had two and had transmission issues with both.
Our kids have a Ford F350 Duramax, and the Cummins will out pull it on a hill loaded heavy, but equal. But their transmission is way smoother than mine, and it has a bigger back seat, and some other things I like better. They always show up a few seconds after we get to the top, but I do enjoy passing them.
On our 3400rl our pin weight goes from 2700 to 3500 lbs. Yours should be a tick less. I wouldn't think of putting that in the back of any 3/4 ton. But a lot of people do. In my opinion it better to have too much truck, rather than wishing it was bigger. Especially when your coming down that mountain pass, the brakes are getting hot, your knuckles are white... and then, god forbid, you have a blowout.
There are still a few 06's floating around with factory incentives. But the picking is getting slim. I think we can get an 07 ordered and built before the end of the year and still have the old known engines.
We put air bags on our 3500 Dodge. It did smooth up the ride a bunch. What it did was allow it to stay up off the overloads. The air bags we put on will add 5000 lbs of weight lifting capacity. They wont, however increase you axle capacity. Your tires will proabably be the limiting factor. I may be wrong, but I dont think the 3/4 tons have overloads, so it might not effect the ride quality as much as it did for us. But it will pick up the rear end and level it out.
So what kind of response did you get from the Dodge guys forum when you asked about the Duramax? I bet it was all good.
Happy shopping, its giving me a headache.
Let us know what you end up with.
TimK