Sounds are hard to diagnose because they are hard to describe. It could be bad u joints, bad or broken sway bar links, bad shock, t- case shifter linkage, and the list goes on. Your best bet would be to upload a video of the sound to YouTube and then post the link on here for us to hear so we can give you a better suggestion.
oh and do you know where the sound is coming from? Front, rear, or Side that will help narrow the list of could be's as well