I have a montana 4340 and just purchased a bush hog for it. i hooked it up, turned it on and the pto will not turn off. I have pulled the fuse which had no effect. i removed the valve from the block on side of trans that engages the pto, put the solenoid on it and turned the pto switch on and off, can see the valve moving. anyone have any problem like this? know what i can check or do to fix it? any knowlege of how it works? thanks in advance, Jason