rehashing an old thread,
i have a similar issue, hard to get out of 4wd once engaged, sometimes can roll it back and forth to get it easier. could it be something like a shift bushings at all?
4wd drives and functions fine, i have a 3.9 rear dif (cars '92), has to be forced out of 4wd, no clunking or anything when it shifts as the OP of this thread had.
so I have went to the practice of just using 4wd on snow or mud. dry/wet pavement still binds up and makes it difficult to get out of 4hi.