I have pretty bad luck when it comes to this type of thing.
Was working on stuff in the cab of my 62 D200 and dropped a 3/8 nut, which - I still cannot believe this - turned sideways and went straight into the hole in the steering column... and disappeared.
I can't get my scope in there to see where it is. Would it have slid all the way to the bottom of the column and come to rest on the rubber gasket above the steering coupler, you think? I will try to get a flexible magnet but it's going to be hell because it will just stick to the steel of the steering column.
I guess it would be sitting on this seal at the base of the column jacket tube, assuming that seal is still much intact... if it was a smaller nut I wouldn't be as concerned but 3/8" seems just large enough to somehow bind up in there.
If you have a strong enough magnet maybe try from the outside of the tube and drag it up to the top where you can grab it with needle nose pliers. Or try wrapping electrical tape around the outside of the flexible magnet so it doesn’t work as well on the sides only at the tip.
Good luck
Late 65 w 200.
Factory LU-2 winch.
Updates: 205 transfer case,4.10 gears, disc brake Dana 60 front with lock out hubs
440 repower in the works