Grand Prix Clunking HELP!!!

I have a 94' gp 2dr. with 4 wheel disc. My problem is whenever I back out of my driveway when my passenger rear tire hits the road it clunks. I assume it is something with the suspension. Any Ideas what is causing this??? Any help is appreciated!!!

Well if it was in the front it would be the (cv joints) with means theres play an u need to replace them they only get worse an cant fix the old one's need new,,,,, is you driveway on a angle like the front of you car higher than the back when you goin out backwards? if so have someone stand outside an listen it might be the cv in the front on the right side - its hard to hear from inside but does it make any noise's on hard cornering i dont me like 30 mph on a 60 degree turn but like 45-50mph on a corner... if it clunks it is defenately the cv joints -they run about 150 green backs to get replacements..... give me more descriptive things an i could give you a better answer... need to know exactly where the noise is .

yeah, my driveway is on an angle, so like you said when I back up and hear the clunk it is when the front end is higher than the rear. I have had somebody stand outside the car and it is definently the right rear. Hope this helps.