The LMM (07-10) and LBZ (06-07) Dmaxs seem to be a pretty solid engine, while the 6.7 Cummins seems to have a few issues. Both trannies, either the 68re with the Cummins, or the Allison with the Dmax should hold up well.

I personally would go with the Dmax. I like their bodies a lot more, and their interiors are far superior the dodges in style, quality, and comfort IMO. Throw exhaust, intake, and a 60-90 hp tune on there and you should have a good, reliable family vehicle

 

Hey man I dont know if you are willing to go this old but for bang for your buck, you need to get a 7.3. You can get a great one for less the 15 grand. And they just DONT die.