I stopped mowing today when the sound changed on my 1025R MMM. I was able to turn the male coupler by hand without any movement of the belt. I located the two allen set screws and one was very loose.
After tightening the set screws I attached the mower and pulled the yellow mower switch. The same symptoms. Not mowing.
Any ideas? My searchs here came up with the following photo. My operators manual is useless, they don't show any coupler.
I have about 3 weeks left on warranty.
Meanwhile is a 30' Grady White.