Standing AC unit works but makes horrendous screeching noise all the while

It's an 8 year old York unit that has worked perfectly for the couple years I've had it. The other day I had it on for about 30 minutes and the entire time it made this deafening screeching noise. It worked fine and pushed cold air. I took off the tube that goes to the window and nothing was clogged. The water receptacle wasn't clogged either. I turned it on a couple more times, same thing. Salvageable or time for a new one?