Hey guys! I've got a loud, almost scratching sound when I start my Hummer. It goes away after driving for awhile. I replaced the tension pulley and inspected everything else with a stethoscope. I think the noise is coming from the alternator. I cannot find a pulley just for the alternator and was wondering if that's even an option to replace instead of having to replace the entire alternator? I come with full reverence asking for your expert advise. Thanks.

 

Noise from any pulley is due to worn bearings.

 

the pully is a pretty solid piece i doubt that it is the issue unless the nut is loose.
if your alternator has a cooling fan blade behind the pully make sure it is not scraping the housing.
but most likely it can be you have bad bearings in the alternator. remove the belt and check it for axel play and smoothness when spun. if it sounds dry or feels loose or notchy then the bearing are going.

 

Gotcha. So a new alternator it is! Thank you. I bow to you humbly.