3 speed column shifting weirdness?

TrailBeast said

Sounds like a linkage detent/lockout not being where the lever can move.
(an adjustment issue)
Does the shifter itself work normal when disconnected from the trans?
If they both work fine separated then you know for sure it's a linkage adjustment problem.

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That is actually something I hadn't tried yet, so I just did. Unfortunately, with both shift rods disconnected from the column, the shift lever still only moves up/down. It won't budge to move it over and select 1/R.

One other thing to mention: Turning the steering wheel causes the shift lever to move up and down slightly. I suspect that SOMETHING is stuck between the actual steering shaft and the shift components, though I didn't see anything when I partially disassembled it a couple weeks ago. May have to yank the entire column and completely disassemble it.

Thanks for the new ideas!