I just noticed a clumping sound when this furnace turns off... and suspect the blower wheel. How can I be sure short of dissassemblng the whole creation? I have found the parts online if I need to order them. Is it the wheel or something else in the blower. The sound is reminescint of when you slow down a bike tire and it is rubbing against something.

The blower motor shaft sometimes wears the slip sleve bearings out in the motor allowing the shaft to move back and forth during power up and especially when the furnace blower cuts off. The only way to tell is to take it apart and have a look see unless you can get your hand or a few fingers on the blower wheel. Then you can try to move it in and out to see how much play is there. Cut power off first. Replacement fingers no longer available. LOL Merry Christmas.