Without going into too much detail,  my basic sympton is that when I try to go into 4wd, I hear the mechanics below the vehicle with what sounds like  a few attempts to physically engage  (not sure if its the shift motor or not), but then after a few attempts, it seems to fail and revert back to 2Hi.  I believe this is the case for both 4Hi and 4Lo.  Dont recall on effect of Auto 4wd switch selection off hand  (been awhile,  doing this from memory)  No leaks,  definitely has good trac II  fluid and not mixed with tranny.   I suspect either the shift motor or the case itself, but Im not much of a car guy.  Obviously trying to eliminate the easier stuff as possibilities before surrendering to having to have a rebuild or swap of the case itself.  Any thoughts on core of the issue or other things to check/data to collect? (Incidentally,  I looking around for another NP246 now to rebuild anyway as a learning,  already did the engine..too afraid to try the tranny so far).