I just replaced my alternator with a Bosch unit from NAPA. Now I have a squealing sound coming from the alternator area. I checked the belt tension and it is tight but still with about a 1/4" give. With the engine off if I push on the belt near the alternator I can hear sort of a scraping sound coming from the alternator. I'm trying to figure out if I got a bad rebuilt unit or if I did something wrong on the install.