4wd not working on 1990 sportrak


any ideas why it might do this? all i know is that only the back wheels are driving in both 4H and 4L. a guy at mudbugz told me it could be that the free wheeling hubs are broken. if they are broke is it worth gettng them repaired or just to get a new/second hand pair ps if anyone has any for sale i might be interested. cheers