How to Troubleshoot & Replace Ge AP3415693 / WB02T10017 Nut

Got an F9 error code 3 hours into a 4-hour self-clean cycle. The technical data sheet said the likely cause was stalled cooling fan in the control area. Replace the fan and clean/vacuum the entire control area. The hardest part was removing all the wires from the control board to get it out of the way. Be sure to either take lots of pictures of where all the wires go or make yourself a sketch. Heard clunking sound as the convection fan was cycling off. Discovered that the fan blade was loose on the motor post. Replace the fan nut. The trickiest part was having to discover that the fan nut is reverse (left-hand) threaded. It sure would have been nice if the technical data sheet warned me about that!! 

Replace the lost nut, thanks to appliancepartspros for the part provided. 

Replaced convection motor. Since I would have it apart, I replaced the convection fan and nut which was a good idea because the fan bent while trying to remove the fan nut. The convection fan was rusted out and looked terrible so, a very worthwhile replacement. Repair took about an hour because I had to remove the wall unit and this involved disconnecting electrical power and the microwave above the oven.