when the front 4x4 engages, that thing we all know about expands, grabs onto the hub, and spins it.

Well When mine "grabs on" to the hub, the inside of the hub spins freely, the disk or something. I'm unsure what it is called, Here is an image



The arrow points to the disk inside the hub, this disk spins freely, so when the 4x4 goes to engage, and lock into the hub it does so but that plate spins inside the hub as oppose to spinning the hub.

Looks like there is something i can do to tighten it, but the tool required isn't known to me. If anyone can help, that would be highly appreciated.

 

looks like it had water in it at one time.