94 mustang ebrake rubbing drive shaft.

Maybe you have the same problem I did...

Have a look under at the floor pan area above the pinion on the differential, there should be a metal plate and a rubber bump stop mounted to it (called pinion snubber). It limits the upward movement of the differential. When I bought my car, I had the same problem, and noticed this piece had torn-off somehow and was gone, so I just bought one for $10 from MaximumMotorsports (the non-adjustable one). I just sanwiched the metal plate between 2 big flat washers so it won't just rip itself off again.
Also make sure the "dogbone" upper plate is still bolted to the pinion housing. This is where the pinion snubber will make contact with the differential.

I never heard any driveshaft grinding ever since.

I did the same thing 1tallMF did-I never had that problem come back.

My ebrake bracket was bent down from the floor pan. I took a hammer to mine then screwed it in place...

check your tranny mount also