I am changing the transom mounts on a 84 35HP motor. I know I need to remove the 2 bolts on the drive shaft housing to the bottom yoke. I think I then need to remove the retaining ring on the bottom of the swivel pin. Is the ring threaded? Never seen a nut like it before. How to I remove it? Looks like when removed I can lift the motor up off the transom mounts then.