Hard to really say until you isolate it. Could be the replacement part. Could be a tensioner or idler pulley, or really any of the other ones. Remove the belt, spin each pulley and see if you can isolate it.
Thanks DaveJM, there was a video of a guy doing this on youtube even removing the engine mount bolts and ac connections to raise the motor for more accessibility, but that would be beyond my capabilities. He found a pulley that needed bearings lubricated, we'll take it back to dealership that replaced alternator to see if they can resolve the problem. Thanks again for your quick response.
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Thanks DaveJM, there was a video of a guy doing this on youtube even removing the engine mount bolts and ac connections to raise the motor for more accessibility, but that would be beyond my capabilities. He found a pulley that needed bearings lubricated, we'll take it back to dealership that replaced alternator to see if they can resolve the problem. Thanks again for your quick response.