97modifiedmustangGT

I have this clunking sound coming from the rearend when i turn right. I have to be going about 10-15 miles and hour for it to clunk. It will not do it if you are say stopped at a stop sign and then start to turn you have to have speed. I am wondering if it actually is the gears. what exactly clunks, is it the ring gear or what? I am also thinking and hoping it is just my exhaust hitting the frame where the exhaust curves over the axle. it is so close to the frame rail that i think this is most likely what is making the sound. I have loosened the exhaust and pulled it over so is has some distance from the frame but it always finds a way back there lol. so i guess my question is if it is the actual rear end what clunks in there?