Np231 questions..yes ive read dozens of posts first

Hasta Yes to this im newbish...built many a hotrod but never done more than 3" lift on a jeep.. SO I have a 93xj 4.5 lift coils , rustys long travel radius arms, full 4.5 leaf rear, No SLE(rustys crossmember drops tcase about 1.5" so tcase drop? yeah kinda), stock np231. I just bought so working out the issues.
I took it on the 1rst test run and it popped out of 4low and grinded like hell
I brought it home and installed AZZYs linkage and still have grinding in 4low.
Linkage is adjusted properly, no vibrations on road, good motor and trans mounts.
So at this point im thinking the tcase low range gear is damaged, or forks, chain etc.
It will engage 4low, drop into lowrange and pull but make noise...and real torque and it pops out and starts chattering. Seems to be fine in 4high hastas

If what you say is true, I would go along with your conclusion.

Take the linkage off the shifter arm at the case and manually engage 4L. See if the issue persists.

Does it have oil in it?

Sent from my SM-G960U using Tapatalk