John Deere S-series PTO shuts off by itself

[pgeon1]

I am new to this forum. I have a John Deere x595 and when mowing my deck shuts off unexpectantly by itself. It seems like it needs too cool a few minutes and it will restart. but the time it stays engaged decreases each time unless I let it set for a extended time. I have put a new PTO switch on the dash but it didn't help. Is something over heating? Thanks in advance for any help.
Jon