Noisy fan please read and comment?

That fan has a narrow and long squirrel cage blower .The motor is in the middle and there are two cages off of each end of the motors armature, which is mounted vertically. One or both of the cages got a little bent and is most likely touching the housing as it spins. If you listen to it carefully after you switch it off and as it spins down, you'll hear the ticking sound slow down and eventually stop, as the cage comes to a stop. You might be able to push on the cage through the air vents with a screw driver but you have to do so at the right place and bend it back in the place you need to. If you adjust it in the wrong place it will just get more out of alignment and you'll make it worse. It may be corrected by opening it up and straighten out the wobble of one or both cages. SS