The rectifier doesn't make noise unless it has physical damage and the rotor is interfering. Sounds to me like you'll find exactly what CeeBee is talking about. When the rear bearing seizes, it makes a mess of that plastic cup that seats it in the housing casting.

To get it all apart and replace the bearing, plastic cup, and (in my case) slip rings you'll need some gear or bearing pullers, a press or large vise, and a heavy-duty soldering iron.

I don't know an easy way to test the rectifier assembly. You need it run in the car, or a stronger bench-mounted electric motor than I have, a carbon pile load like you test batteries with, and an oscilloscope. Don't know, but I doubt the auto parts stores can do much more than check the output current/voltage. I'm probably wrong about that assumption.
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Art Benstein near Baltimore

I'm so busy I don't know whether I found a rope or lost my horse.