I assume these are indeed AUTO hubs?

If so, your description may or may not be just the way they work. The loss of the c-clip on the end of the hub is usually more of a problem with the manual hubs. The AUTO hubs use the smaller diameter on the very end of the hub and seem to have the problem less often.

They work by locking via a difference in torque between the axle and the hub. Well, as long as there is still a difference between those two, they stay locked. If slack (or no difference in torque, or a reversal of torque) is present, they unlock.

This is why they can stay locked even if you shift to 2wd and why you have to back up a bit to get them to unlock.

But, it also means if you are rocking it at a bad spot in the trail by shifting between forward and reverse, they tend to unlock. It also means if you bounce a tire, they can also unlock. I've heard these things sounding like they are going to come apart during a hill climb.

So, add in some age, add in some sticky grease and they may just be preforming poorly. The ultimate solution is to convert to manual hubs. The AUTOs are just not worth the time to screw with them.

Also, WARN makes hubs for our vehicles. They seem to be a bit more stout than the Superwinch hubs, but the stock ASINS are also considered to be bullet proof.

Good Luck,
Michael