Does your PTO have the five pipe plugs in the rear of the case? I have a Koenig 51 and it has pipe plugs, and my only guess is that you remove the pipe plugs, and reach in through the holes with a socket and extension and remove the five bolts that fasten it to the back of the T/C...If you've done that, and it still won't budge, maybe you can remove the back cover of the PTO and see what's holding it on there...