Removing starter from 964
 

I am removing the starter from my 91 964. The manual said that I shouldn't have to pull the engine and transmission. I've been able to disconnect all the wires and barrel head nut from the bottom of the starter, (obviously working from underneath) but I can't get the barrel head nut from the top of the starter. Is there a special tool I need or some insight into removing this top nut? TIA