The noise might be caused by a loose chain inside the transfer case. Or you could have a faulty U-Joint on the front propeller shaft. It is unlikely that the U-Joints on the front drive axles are causing the problem because you don't hear it when turning.
thank you for your help. i had it checked out, and it was a bad front driveshatf. now i need to know how hard is it to change for someone that is somewhat, but not great at the mechinical side. just never replaced anything like this before. thanks again
If you are sure it is a bad front driveshaft, Good luck. Just remember both front driveshafts (or half-shafts) enter the tranfer case as well. So I don't know what kind of check was performed but good luck to you.