Alternator noise?

So my factory alternator on my 11' was making the whine that I guess can happen so I put in a new one. The factory belt would squeal off and on but the new alternator was quiet. I replaced the belt with a new one and now the alternator is making the same noise as the old one. WTF is going on here?

 

Are you sure it is the alternator and not a pulley trying to go bad?

 

Not completely sure but the noise sounds like its coming from the alternator. I checked all the other stuff run by the belt and the fluids are all good and and they seem quiet.

 

What kind of condition is your battery in? Sometimes if your battery is struggling to take a charge the alternator will make noise as it may be working overtime to charge the battery. Crank your truck and while it is running turn on your headlights (high beam)and add more of a load to the alternator see if the noise gets worse. just my .02

 

I went thru a similar situation this past summer with a 2015 V6, but the noise was an oscillating sound. I could clearly hear it with a mechanics stethoscope held to the alternator.
This was a warranty issue.
After the dealer mistakenly replaced the a/c compressor, they ended up replacing the belt tensioner, belt and 2 pulleys.

 

The battery is 2 years old. I’ll check it tonight with the lights on.