Greg, I have changed the oil (twice, once when new, and at 100 hrs), checked level in gearbox and hydrolic (both ok), disconnected hog, switched to N on speed. Gears from 1 thru 12 foward and 1 thru 4 reverse. Noise sounds like it is coming from rear end or under seat, but could be somewhere else. It is a grinding noise somewhat like trying to shift gears without having clutch completly depressed or the tractor is still moving a little, only it grinds when you let off clutch or depress clutch pedal, with or without pto being engaged or dis-engaged. Pto when supposedly dis-engaged, will rotate slowly, can stop by hand, but will rotate slowly if you let go of it.
The Noise seems to start when you let off clutch, in what should be the PTO stage, noise quits at top of pedal, but starts up again when you depress clutch, and get to what should be the PTO range. I have not pulled off clutch inspection plate yet, because I dont know what I would be looking at or for other than obvious broken pieces, but I plan to do that this PM. This noise started when hogging, I came up next to a place that I wanted to inspect before my next round. Pushed in clutch to stop, and grinding started. I really dont know exactly what I did next, I think I tried to knock it out of gear first, and then dis-enguage PTO or maybe the other way around. Anyway grinding continued, so I put it back in gear and let off on clutch and grinding stopped. Pulled out of the weeds, and finally got it in N in gears and PTO, no noise with pedal completely depressed, but some grinding as I released pedal. With everything in N, grinding would continue as I pressed and released clutch for a couple of times, then stop. If I then pressed clutch, no noise, move to a gear, release clutch, grinding occured. Pressing clutch, moving back to N. Grinding would be heard when pressing clutch for a couple of times, then stop.
After re-reading this post a couple of times, I am confused as heck my-self. So I can imagine what you will think.
Rocker is probably right about the sound fixing itself.