We're on our second diesel truck for general use and towing to and from race events. We have our second Duramax (GM diesel) - and are satisfied very much. Of the three name brands of trucks, the Dodge, with Cummins diesel, is the noisiest, the Ford Powerstroke the middle unit, and the Duramax the quietest (at least form the outside. I haven't ridden in anything but the D-max). That alone is worth quite a bit to us.
We get about 22-24 mpg in daily driving around home in the summertime and about 19 in the winter when we're in 4WD for months at a time. When we tow the race trailer we get in the 14.5 - 15.5 range. The rig total scales at 13,300 - 14,000#, depending on what's in the trailer (we drove across a scale last week to check once more). I don't complain about our fuel economy. I offer one caveat about economy -- we drive at or below the speed limit always. If you want better mileage -- KEEP YOUR FOOT OUT OF THE THROTTLE!!!
Our first diesel was traded in at 250,000 miles because I wanted a new truck before the diesel engine fluid additive became required -- so we've got an '09. The '04 that we traded was fine -- no loss of performace, no increase in oil consumption. I had carefully changed the oil, which was Rotella 5W40 synthetic, every 25,000 - 30,000 miles (no error there). I change filter halfway between oil changes.
Don't be afraid to ask for maintenance records. If the engine looks to have lived a good life -- go ahead, get one.
