190XT Clutch - Transmission Issues

My 190XT has an issue that developed last fall where the transmission when in low gear doesn't fully disengage when the clutch is pushed in.   The tractor would continue to move and if it ran into resistance (slight grade) it would stop.   I checked fluid, it was low so filled it and problem seemed to go away until the tractor had been run for quite some time and was warm and then the problem began again.    Is this an issue with the clutch or other components in the transmission? 

Pushing in the foot clutch stops all power to the power director and the PTO at the same time
If your tractor doesn't stop with the foot clutch pushed it has nothing to do with the transmition.
You have a clutch dragging. Has the clutch free play been adjusted? If it's correct the problem is in the clutch. The clutch is warped, covered in oil, wore out and adjusted improperly, or the throw out bearing is toast. My first guess would be covered in oil. Either way I don't see you fixing it without splitting the tractor and taking a look. If it's an oil covered clutch I have had some luck on a C pulling the starter locking the clutch down and spraying the clutch full of brake cleaner while slowly turning it over. It did of course come back in about a month so I split it and fixed the clutch fork. It wasn't disengaging because it ran out of adjustment before fully disengaging.

i split my tractor it did the same thing had to shut off to get it to stop.  when split i found part of the clutch disc wedged behind another pad so by pushing in on the clutch it had enough friction to keep it moving