Alternator screech ??? but I still get 14 volts

output and the bearings dont really have anything to do with each other, until the bearing siezes up, then your output is zero! try this; start your car, and take a long handled screwdriver, hold the blade against the rear bearing of your alternator, and put your ear against the handle.now, carefully hold the blade against the waterpump housing, as close to the bearing as you dare.it doesnt take long to get the hang of probing around the engine compartment to figure what parts generate which noises. just use a little caution around the fan, belts, pulleys, etc...

spray a little carb cleaner or window cleaner and see if the squeel stops to make sure its not the belt, but a bearing can be bad and still put out a charge

I had a prob with alternator screech getting progressively worse. Tried replacing the belts a couple of times, was about to replace the chrome pulley when someone recommended a new battery. I was already using a optima redtop but I figured it was worth a shot. Sure enough, I replaced my expensive optima with a "cheapie" and problem gone. No more pulley screech. Good luck.