What kind of mileage will the cummins turn in?
Unloaded and with the taller gears, 20+. I can get 25-26 out of mine unloaded, on stock tires at about 58 MPH. My dad's 04 beats 20 if he keeps the speed down a bit. My worst was 9, camper on, wife driving, floored into a headwind. (Rear tire wear was also significant on that trip.) Usually get 13-14 with the camper.
What years to watch out for, which are best?
Pre-96 have rotary fuel pump, less durable. 96-98.5 have inline pump, very durable. 98.5+ have rotary pump, very sensitive to low fuel pressure, are destroyed by it. 03+ are common-rail, dunno much about them. HP increased stepwise year by year.
What about the tranny? Have they got that problem fixed yet?
I believe so, new trucks are pretty durable. Tranny (either) is the weak sister of the drive train, up to fairly recently. -- Jim
