Thanks for trying guys! Chilton, Haynes & the FSM all say the same: 'Remove the PS Pump...' then they go right into how to rebuild it. The woodruff key sits between the shaft and pulley; it locks them together so that the pulley isn't just spinning on a hub. Can't get to it w/o taking the nut off first. The shaft is a standard thread; I can see the very end of it outside the nut. The new pump is a standard thread also.
Anyone else?

'89 4Runner, V6, Auto, 180K, Some stuff's stock, some isn't.