I'll check 4lo when I get home from work. Took the wife's libby today so mine wouldn't get any worse. I never had any issues in the Bronco with tcase or diff fluid and that was up to 170,000 mi. But, no limited slip or clutch packs in either, so it was quite different. (don't have clutch packs in the xk diffs as it is QT2, but the t-case likely does).

If it does work in 4lo after I drive it long enough to exhibit the problem could a fluid change fix it or are the clutch packs shot?