Hello, and welcome! Now, about that noise, my thoughts would be any of the following:
PS pully/pump, AC compressor (mine screams)
(saw someone mentioned a timing belt / pully in your Welcome thread)
Trans or diff internal issue... could have been the reason Previous Owner flushed it
Rubbing at the wheel - dirt, brakes, etc. Since the noise is intermittent this'd be less likely, though I have a noise of my own from wheels that disappears under braking...
See if you can track it down to engine, transmission, or wheels. If you lay on the throttle in neutral, does it go away? Coasting downhill vs descending under power? Limit to 2nd, 3rd gear? If nothing else, get it (carefully!!) on four jackstands, or two + FWD fuse, and push the pedal slightly?