96-98's 249's have an actual locked 4LOW, 93-95 249's still used the VC (viscous coupler) when shifted into 4LOW so it's not really locked. The VC's on all of these 249 cases usually last about 100K so depending on the mileage on your vehicle you might or might not have some life left in the case, and if the VC goes out it can be expensive ~$600-$1000 to replace, so in those circumstances a t-case swap is a "cheaper" alternative. A good test at seeing if the VC is going out on a Jeep is driving it for about 20-30 mins to get it to operating temp, then in a parking lot do a series of "8" maneuvers. If the jeep can idle through the series of "8's" then you are good to go, but if the steering feels like it's binding or it feels like it's lurching forward or "hopping" forward or you have to give it gas to make the turns then the VC is on it's last legs... Hope this helps <img src="/forums/images/graemlins/cheers.gif" alt="" />.

Fred R.