I pulled the top cover off over the top of the PTO and found the chain links to be in like new shape. Turned the shaft...quiet and smooth. My guess is the broken link I found at the bottom of the case probably broke a while ago and was repaired.
I pulled off the reservoir for the oil bath air cleaner and it was dry as a bone. Do these tractors suck the oil out of the air cleaner?
Thsnks for all your help with this project!!