:Think how the system works as a rotating unit. All three are dependent :upon eachother to work. If alternator is noisy it has to be the rear :bearing that is housed in back of alt. Its the only thing that can cause :friction due to wear thus making a noise. That said the bearing rides on :the rotor and stator shaft if that shaft is pulled to hard at an angle it will :put that rear bearing in a bind and there is prob. Question is what is :pulling on the alt pulley to do that? So typically its the idle pulley because :its the weakest link in that system. That pulley should have no wiggle :movement nor should it have a rough roll to it. But, anumber of other :issues may be at play...the alt bracket, the actual bolt that hangs the :alt...is it outta wack. Like u said fan clutch ..does it seem to work ok. Just :start checking but usually its that damn silly pulley!