Originally Posted by kahanabob
I can say that if i gave it a fast twist it would stop turning immediately. I hate to just start trowing parts at this.
Just had my alternator seize up on me, and the belt was squeaking like crazy just before. I do think your alternator should keep spinning when you give it a fast twist though. Not so much as say, your water pump or power steering, but I don't think it should stop immediately.
Most auto parts stores can test it if you bring it in, or, like others have suggested, find the thread and learn how to do it!