I have no experience with that particular axle, but on many types of 4wd front axles they use small king pins top and bottom, with bearings as perviously mentioned. Under the king pin cap is a stack of shims which is used to set the bearing preload and as a means to take the vertical slop out as they wear. Usually is a 4 bolt cap, with grease fitting in the king pin. On older equipment often the previous owners have already taken all the shims out to try to get the slop out when everything is worn past spec.