FRPP Driveshaft
 

I got the new Ford Racing Driveshaft about 2 months ago and haven't had any problems until recently. When I tap on the gas I can hear a clunking noise which seems to be coming form the driveshaft or where it goes into the trasmission. I know it can't be the u-joints, I've been driving on a bad rear trasmission seal for awhile now, just haven't got around to changing it. Also been noticing some vibration from the same area, Does it need balacing, or is it the bad seal??