Yesterday I was running the tractor when I started hearing a loud THUMP, THUMP, THUMP of something hitting the floorboard of the tractor from underneath. I had the mower deck on (but not running) and could not see anything. I took the deck off, climbed under and found (attached photo) the boot where the main shaft comes out of the engine decided to rip and fly around with every revolution of the engine. But seeing how it's just a boot to keep dirt out of that connection of the shaft, I don't think it's necessary as long as I don't drive in a swamp. Any other opinions?