Hey picked up a Bush Hog 105 5' rotary mower at a farm sale last weekend. I took care to clean, greese and check gear box oil. Worked great for a week. Yesterday blades stopped spinning. I opened gear box and there were teeth everywhere. I had ear plugs in so may not have noticed first signs of trouble. Both gears are done for 15 and 21 tooth. Question is what caused it, bad clutch? Frozen clutch? And what other damage should I look for while I have it apart. What kind of damage goes along with something like this? I was using a Ford 8000. I know this is a big tractor for a small bush hog but I need the small mower for small areas. Thank you for your time.