Odd noise from rear of 91 GSX

[MattZ31]

I was driving around tonight and started noticing a noise above the loud Walbro pump. Right at 70mph there was this odd noise from the back end. Then later on I noticed when I let off the throttle and the car wasn't being really loud, it sounded like there was a scraping noise. Kinda like the sound would be if you had your brakes on and kept driving, how the brake pad rubbing against the rotor might sound. It didn't let off when I hit the brakes, it seemed to decellerate with the car until I stopped at a light, and it would stop. Do ya think maybe the rear diff is running low on juice?

 

[TimmyD]

I've had that noise since I bought the car two years ago. It's either a wheel bearing or the brake dust shield rubbing against the rotor. I would think if my rear diff was low for that long, it would have died by now. Mine is def on the passenger side.