[JRSIII]

I've struggled with that nut for over an hour. I finally got it loose by putting a small socket on the nut without the ratchet because there is no clearance, and then clamping the socket with vise grips and somehow wedging or holding the vise grips to prevent the nut from turning. However, if the tip about removing the filler panel works, it's definitely the way to go.

Note that when I reassembled, I replaced the nut with a speed nut, so that next time I won't need to hold backup.