My furnace started rattling a couple months ago And have been putting off looking at it as it has been working fine. Tonight I decided to see if the set screw was loose on the blower it was pretty tight I decided to clean it as well and got it looking brand new after aligning and putting everything back in the noise is still there any ideas of what this could be?? It only happens when the unit is on after it turns off the noise Disappears even while the blower is still rotating and coming to a stop. I checked the motor The shaft had no side to side movement and very little play up and down any help is appreciated it’s a trane unit and electric not gas.