Ok, did some more testing today. Decided to pull the oil pressure regulator from the bottom of the transmission, below the PTO valve. Found 8 shims in the assembly. Removed all the shims, tested the PSI at about 120 and PTO would not shut off at any RPM.
Replaced the 8 shims and inserted about 4 more shims (washers) and that brought the PSI to 180-185 and the PTO now works correctly.
Now the question is why do I need the PSI on the clutch port to be 30 PSI above the specs called for? Is this going to hurt anything to leave it this high? I guess I could remove a few washers and maybe set it down to 170-175 and see if that works. I could live with some no load rotation and set the PSI down a bit.
One other question, would setting the PSI up this high cause any leaks from the front of the transmission input shaft? I have drips about every 8 seconds coming out the weep hole in the bottom of the bell housing now? :(
Anyone with a powershift care to chime in. How much spin is normal after turning off the PTO at high RPM"s? At 185 PSI, the pto shaft without anything hooked up stops immediately after shutting off the PTO lever? Am I expecting too much from a 46 year old tractor?