Our stock locking hubs were toast when we bought the truck. Someone who shouldn’t have was clearly trying to “fix” them. One hub was missing internal parts and the other was simply broken. We threw them out and slapped in some new 30-spline Warn Premium locking hubs (PN 38826) to get our four-wheel-drive system functioning again. This was by far the easiest and most effective upgrade we have made to our truck.