Shifter Problems...

That's the reverse rod; funny you didn't mention reverse doesn't work.
If you have forward motion in first gear, then it just fell off and has nothing to do with second.

However, if I understand you correctly, that you can actually put the trans into second, and it stays in second; and then when you let the clutch out taking your foot off the pedal, then gassing it produces no forward motion, only grinding ; if I got that right, and first gear is fine... then the trans has to come down because second gear is fubarred.
>But if it grinds while you are trying to put it into second, but not yet in; that's a different problem; the brass ring is wore out or the synchronizer is defective; but the box still needs to come down.
<But if gassing it in second produces forward motion, but it likes to kick out the shifter and thats when it grinds; that's a different problem;Second-gear clutch teeth need reparing; but the box still needs to come down.
>But if gassing it , while second is fully in-shifted, produces smooth forward motion PLUS grinding, and it didn't do that in first, IDK, could be a couple of things none good, so the box still needs to come down,lol........ unless the reverse gear is no longer synced to the lever and is just floating around in there; but to fix it the box still needs to come down,lol.

That A833 transmission is about as simple as they get, so don't be afraid to open it up.
I tried to think how the upside down lever could affect the 1-2 gate, and I'm stumped. If you get first, then you should get second. If it locks up in second; then you have two gears at once, and Ima thinking that can only happen if the reverse idler gear is no longer synced to the reverse lever.