Currently have the '01 Cummins diesel dodge truck automatic. Heck of a towing machine that's for sure.
We have more aftermarket gauges then you can spit at, as we tow a 5th wheel with it, run it off-road, etc. Currently has 120k or so, everything original. Auto tranny hasn't skipped a beat; we do change the fluid every year and we are not rough and fast drivers either, I do believe that helps with longetivity.
We have always, in the past, been die-hard Chevy truck fans. Still are, however, we were burned pretty badly with the last 3/4 ton '99 Chevy 6.0L Vortec gas engine.
Truck had great power; gas mileage was half, however, of what we can manage in the Cummins. GREAT ride, cab space, etc. however, this particular one was a 5-spd, in which the throw-out bearing kept going out, brakes WERE horrible all around, engine kept throwing out the freeze plugs, main computer went out twice.
Aside from that, it was a beautiful truck...just got tired of constant issues and it only had 80k miles on it.
We looked to trade it for a Duramax, but never could find a reasonably priced used one. In fact, I could've bought 2 Dodge diesels for the price of ONE Duramax....it was just too ridiculous for us to keep looking.
The Cummins 5.9L HO inline 6 is a he$$ of an engine; can't speak for the newer ones though as it looks like we won't be needing one for a LONG time.