Just bought a 04' Ram, 4,7L 2WD quad cab with 198,000 miles on it. Should I change the tranny fluid? I think I should. Also what else should I do. I just changed the water pump and thermostat the other day. Thanks.

 

I would change the tranny fluid, cause you don't really know the maintainence history. It wouldn't hurt to give it an oil change and check the plugs too. Mind as well start fresh, so you know it's been changed. Just my two bits!

 

You probably will need to change it several times to get everything out and get all the stuff that's going to get loosened up by the new fluid with it's new cleaning agents. Change the filter a couple of times, too. I would change it, drive a thousand miles or so, then change it again, etc. until the fluid coming out looks like the fluid going in, and the pan and filter are both clean. That's a lot of miles to build stuff up!

 

I treat all used cars as if nothing had been done. At 200K miles, you should do all the routine stuff, and just assume it had never been done. Plugs, air filter, PCV valve, oil, tranny fluid, power steering fluid, brake line flush, differential oil, ... that's just the stuff off the top of my head. Obviously use your judgment on it all. When in doubt, do the maintenance.
I'd run a little SeaFoam TransTune as per the instructions, then change the fluid and filter like this guy did. Minus breaking bolts, it's a good how-to.
http://www.60ateight.com/DodgeRam/

 

If yuo just got a new truck then change everything and do preventive maintenance as if it has never been done before, because essentially, you dont know if it has or when.

 

I like your guys theory of change it all because of an unknown past. I just got done with the water pump and thermostat. New tires go on Monday. Now I just have to figure out why the washing fluid level sensor reads "low wash" even though it has a gallon of it in the reservoir. Any ideas?