Clunking Noise

Hey guys, my 03 cav just hit 36,000 miles, and I've noticed a clunking noise under the hood while driving. Its only really noticable when I have the air conditioning on, and it usually occurs when i hit bumps, but occasionally it just happens on its own. The noise is very noticable in the cab, and it is extremely frequent. Any help would be great... Thanx

oh yea, sorry guys, I also had a problem about a year and a half ago when i had to get my lower control arm and hub bearing replaced from hitting a curb in a snowstorm. I don't know if this helps at all, but I haven't damaged anything since then, and the problem is just appearing..

did you check for loose parts?

I did, but it only seems present when my car is actually driving.. but from what I've checked, everything seems to be ok... (except that damn noise!)