I'm replacing the Gimbal ring on my '76 888 drive and have hit a snag getting the lower swivel pin out. The instructions say to pull the cotter pin and drive the swivel shaft out. I've removed the pin, but the shaft won't move. Have I missed something? The bottom of the pin seems to be slotted as if it should turn with a very large flat blade screwdriver. I've tried mild heat from a propane torch with no results. Any ideas???