A833 getting stuck in 3rd gear

I've seen this before;
If all three struts are popping out;
-Check the back bearing, the mainshaft may be too far forward. Yours looks OK.
-Compare the slider to a known Mopar A833 slider. I seem to recall that other sliders will fit on there but the fork groove is out just far enough to cause this. Yours looks fugly to me.
-Also, and most likely; the brass rings are the travel limiters. If they are worn too far or the grooves are too deep or one is split, then the struts can over-travel and pop-out.