steering shaft coupling

Evening all,
I am planning to use this PS box & pump from an '88 Gran Fury. I have removed it from the car, but an having a heck of a time getting the coupling removed. I removed a plastic pin, and did not see a roll pin. Is there something else in that hole, or is it just rusted up?
I soaked it down with PB Blaster when I stopped for the night.
Any suggestions are welcome!
Thanks,
C