My 2001 Ram has 420,000 miles on it. If you take care of the Cummins motor it will be very reliable. The trouble is now I am having to repair lots of things on the truck itself since the body is showing age and the hinges and rubber seals and things dont last as long as the cummins but that is to be expected. Depending what year dodge you get you might want to poke over to pirate4x4.com too. They have a dodge section and are a bit more about hard core off roading but you can read about some mods and fixes that these guys do on their rigs.