The rubber coupler
I have a JD f915, similar to yours and has the same coupler which has also gone twice in the last 3 years. But only once in the 7 years before that. The one on it now has a small crack in it. I have heard they can go easy but I also heard the engine mount theory. I'm going to check that out since I rebuilt the engine in the thing 3 years ago. I'm also having a problem with the gear box on the 60 inch deck blowing out. If anyone has any ideas on that, I'd appreciate it.