As stated in my other thread...I recently purchased a '96 TA with 95,000 miles on it and there's a noise coming from the rear end that sounds like there is something rubbing together.  The noise tracks with the RPMs...it doesn't get louder as the RPMs increase, but the noise gets faster.

The rear end has plenty of fluid and the fluid looks clean.  The u-joint has no play in it and the stock driveshaft was swapped with another stock piece with no change in the noise.

Brakes?  Gears?  Any help is greatly appreciated.  

It's hard to say in your case, but an improper gear install or a noisy set of aftermarket gears are two of the most popular causes for rear end noise with these cars. The stock posi is also known to be weak.  

tell me about it...this has been a pain to diagnose but I guess I should've mentioned that it's the factory rear end...no gear installs since factory.  It's got clean fluid and we've ruled out the driveshaft and u-joint...  

Have you checked the axle bearings ?  Pull the cover and c-clips, and check the bearings to see if they are shot...they have that sound of parts rubbing together you discribed.  The factory does a good job of setting-up the rear, if it's still stock, I'd look somewhere else  

I had that problem when valvoline changed my diff fluid.  They didn't put in the limited slip additive.  I added some later and it fixed it.