Front end of 2002 dodge ram 1500 2 wheel drive rattles on dirt roads, pot holes, and speed bumps. If I lightly apply the brakes maintaining normal speeds it stops. Checked everything trying to reproduce the noise but no such luck.

When you say it stops the noise when you lightly apply brakes, that leads me to think a brake caliper is loose, coming apart and the pressure of the caliper on the rotor hold it from rattling. Take off front tires and thououghly inspect brakes, grab the calipers and try to move them. They shoud not move at all. Try to wiggle the rotor, it should not move at all either.(except spin normallly) Before you take tires off try to wiggle them hold top and bottom and push/pull. With tires off the ground that is

I've tightened and checked the caliper and mounting brackets everything is tight. Could it be possible one of the pistons on the calliper is loose inside the calliper?

Well, yeah, that's possible but the problem there is I don't see how that would make enough noise for you to hear it in the cab. Sorry I was no help, that's all I have you were a step ahead of me

You've been big help I appreciate it. Forgot to mention I can only hear it with the windows down.

That matters. But I am thinking that if the acuator, or piston, is loose the brakes would not even work. It would get cockeyed in there and not push the caliper. I am grasping straws now...trying...

Well couple years back i replaced the calliper and while taking off the old one my friend accidentally pulled out a piston while trying to compress em to put on. I put it back in tested it out to make sure it was still safe and i have had no problems till now