After test running the tractor with new PTO and doing some mowing, when I shut the tractor down, I heard the hydraulic squealing noise. The 3PT lever was fully down at that point. I did what you mentioned about the feedback linkage above. I adjusted so that there were a few more threads beyond the nut towards the engine side. I could not replicate the noise after the adjustment, but not sure I need to work the tractor for a while to create the same situation as with the mowing test?