I have a cub cadet 2166 which I have owned for 6 years without any problems. Recently the PTO original belt broke or more accurately seems to have melted. I replaced it and as soon as I started the machine the belt broke. I replace it yet again and used the machine for about an hour to mow the lawn and this time the belt shredded and broke after I was done and just rolling up my driveway. Anybody got any ideas of what is going on here?