Well it is electric over hydraulic.. so I would pull the plug on the PTO solenoid and see if the problem is in the switch or is the solenoid sticking, or what..
Do you have the workshop manual.. If not and you intend to fix it yourself, you will sure need it. It is kinda complicated especially with the auto pto microswitch in the fender actuated by the position control lift handle. by the way make sure the auto pto switch is turned off.. I assume you did that already.