Repair outboard spindle on 72 inch deck

I am trying to repair outboard spindle on a 72 inch deck on a 2005 XT model. I have removed the entire assembly from the deck but I am not able to remove the top ring that holds the spindle in place, the ring has two holes on the top and a hole on the side, my question is if the ring screws on and off and is there a tool available from local dealer or is there a way to remove the ring without a special tool.
Thanks for any help.