Well shiiiiiiit! Mowing the old house’s yard after doing the new house. Half way through the front yard I realize I can hear a rumbling from the deck. Slow down the engine, turn blades off, noise goes away...yep...one of the belt pulley bearings probably. Turned it back on and with a thunk the center guide pulley goes flying out. John Deere doesn't make them like they used to. $20 on Amazon and a new one will be here Saturday.