Drive that pin out of the square part. Im guessing. Most are bolted on. Otherwise, pull the top cover off.
That's what I was going to say. That's what that one looks like. Press down on the outer ring and then rotate. Might have to get clever with a tool like an open ended wrench, pliers, screwdrivers, etc.I’m not sure which 4 speed it was, but isn’t there one model that you push down on the shifter and turn that ring counterclockwise and you can lift the shifter right out?