im just a bit confused by your post BUT:
- recently, a new d1 owner tried to "take it out of 4 wheel drive" while exiting the freeway at about 45mph.....
needless to say the noise was horrendous.
with diff lock engaged, that thing skipped and hopped and chirped and bumped along like some scary tranny shit was happening.
take it out of diff lock - hear a big ass bang - drove perfectly fine. he needed a new tcase.
a damaged center diff seems to be your problem. either diff can behave that way as well.
i thought one time i had lost a diff in my truck u-turning out of a parking space - a big bang and some grinding and binding - turned out to be the bolts in my rh front caliper worked loose and the caliper was grinding against the innards of the rim. more lock tight next time....