more problems

[89blacksub]

well it seems as though the front end is acting up now. me and a buddie were sitting in the truck at work and he wanted to see if the 4x4 would actually engage. so i put the tranny in nuetral and he shifted the lever to 4 hi and then i pulled forward a few feet then back to where i was. then we took it out of 4 hi and i reversed it for about 20 feet to make sure that the auto hubs ulocked. later i left work and started heading home. around 30 MPH the right side of the truck started making a sound almost like that made by a kid with a card in his bike spokes. it would stay that way till i stopped. and everytime i stopped there would be a thump-thump and i could feel the struck thumping. i figured maybe the hubs didnt come all the way unlocked but after revearsing for what had to be close to 200 total yards...the same situation. and the thumping when i stop only happens if i go past 30 and the noise starts up again. i dont know what to do...let me know what you think.