Thank You for your reply, the ORC works correctly by hand, I reassembled the rear end and filled it with the old fluid and the pto spins fast for about 1/2 a second then very slowly and I can stop it with any resistance. I drained the fluid and tried running it with the engine and the pto cannot be stopped, which leads me to believe that I either have the wrong fluid or the ORC is worn and only works properly at low RPM's. the ORC in my tractor resembles the replacement part in the TSB that was provided by the local dealership. (there is a pin in the center of the shaft that drives the ORC from the countershaft that is driven by the input shaft from the clutch.) I included 2 pictures of that countershaft, in the TSB the old one does not have that pin it is in the list of replacement parts. the shape of the ORC also resembles the replacement part, not the original. I saw in another thread that there was a detent pin that holds the pto engaged and there was a suggestion to use a bungee cord, I tried this last year holding the pto lever in the engaged position by hand and that did not help. I think I have a single clutch based on the information you provided the power comes in from the clutch, is transferred to a countershaft which drives the ORC shaft and on that shaft there are gears that engage the ranges and from there the power is transmitted back into the transmission. I can drive the various pieces of the PTO out, but I was hoping to avoid extra work if it was unnessassary because the problem is elsewhere, also the "one way clutch" described in the TSB and service manual is a special order part non-returnable that is $262.00. that old post you remember was probably this thread page 3, that is how I knew what I was looking for when I tore into the tractor. the other post I found that gave me the idea of the detent pin is titled "Need advice on NH 1715 PTO Issue"