I have a 96 trcker 4x4 5 speed I put new hubs on this summer and thought the 4x4 was working, I went to use it today and its not. The AWD light comes on and the transfer case ingages, it also ingages in 4 low but does not lock in the front tires. Is it possible the hubs are not installed properly? Or what else can I check? Thanks for the help.