I've got 03 2by4 with 545,975 miles on it, I tow campers with it, so loaded 1/2 the time, fuel milage has increased with millage? empty at 68 I get over 20 aven as high as 24mpg. I'm not asking you to beleive it, because you won't. But it's true. Hard bed cover helps. I've had to reflash the engine once, it would begin to windout without my foot on pedals, only by turning off key could I stop it. I would say the week spots are front steering. I've replaced a total of 4 upper a-arms (due to play)and 2 rack & pinion steering units, once you get play at inner tie rod ends you can't buy replacements, have to replace the whole thing. Also I replaced 2 lift pumps before I put one in tank.
Hope the one in tank lasts. The front wheel bearings will last forever if you take the speed sencer probe out and inject grease into it every year, I still have original wheel bearings. replaced water pump, power stearing pump, rear brahe shoes, Oh the pilot bearing begines to go dry every 250,000miles, next time I will put a bushing to replace it when I change my first clutch disk next summer, same rear end, same 6 sp transmission, same engine, Engine still has the same power as it had new, but sounds a little different. Nothing beats a DODGE, my goal is to get a million plus out of HER.