I have a dodge 1500 slt quad cab with the same motor . I love mine . It has 106,000 on the clock now . No big issues to report . Mine had the in dash blower doors fail at 80 K,needed a new radiator at 90k . I use mobile 1 5w 30 with either a mopar filter or a mobile one filter . I also have the trans serviced the proper way every 30 k and have the spark plugs changed at the same time . Redo the coolant every three years and redo the rear end lube every 30k . I did the power steering fluid myself with a turkey baster . That little v8 has plenty of power for me , I've towed boats , but mostly a utility trailer with a garden tractor on it . Gas mileage is what you would expect from a real truck . The 2006 will be better than a 2004 mileage wise . When I said a transmission serviced the proper way , I mean on a lift with the filter removed and replaced , NOT a flush .