tl;dr
I do not seem to be able to shift all the way back into 4lo or all the way forward into 2wd on my ntm NP242.

about a month ago, I switched my NP231 out for a junkyard NP242. the new case seemed in great condition and installed without any issue. however upon installing it, I realized I had the wrong linkages. the new case came from an automatic, and my xj used to be automatic up until a year ago. so I ziptied the hanging linkages up, and waited until some new parts I ordered on eBay came in.
a week goes by and I notice some crunching if I come out of 1st gear with too many rpms (2k+ rpm). doesn't matter, linkages are here. I begin installing them and the studs that the bracket/brace bolts over are too short. zipties things up, go on to think up a solution.
a week goes by, grinding persists, sounds like tcase, I assume it's because it's not all the way in 2wd without the linkages, etc.
I decide to buy some all-thread coupler or stand offs, basically extra long bolts, and use those to make the bracket bolt in place. that works, everything is finally in place, and as I test out the shifting of the tcase, I notice I can't really get all the way forward(2wd), or all the way back(4lo). I go down below and don't see any issue. I can still drive in 2wd just fine, but I swear it's not all the way in position. as for 4lo, it straight up won't move, which makes me think I'm only able to get back into neutral, the position before 4lo.
I tried adjusting the thing on the linkage that's there for adjustment and didn't really find any solution.
I've also swapped the guide bracket in the cab (the thing the shifter sits in) out for what I assume is the correct one.

I wanted to come here, share some details, and see if anyone had a similar experience or some advice/a direction to look for a solution. also of you have any input as to what my crunching in 1st gear (when +/-2k rpm) could be, that'd be cool too.