progressively louder rumble, especially on startup

Watched the video, removed the front panel, removed the 4 screws from the tumbler frame, and removed the blower cover. Snap ring off, old blower fan off, new one on, new compression ring, snap ring on, Put back together. Done.

Old belt and idler were OK. What surprized me was the amount of lint, fuzz, coins and dust in the blower housing. This was potentially a fire hazard and now its working perfectly and some peace of mind from a fire standpoint. The video really made it happen for me.