Well swapped the driveshaft and replaced the fluid in the transfer case without luck.

Eventually just jacked up the back of the truck and put my wife in it.

With her revving the engine, I listened to the transfer case. There was a little noise but not what I was hearing when driving. Then I walked around to the back of the truck and the rear diff was popping and pinging.

Not positive what is going on in the rear diff but it is the issue. Swapped out the diff last night and today with my spare, have a little clean up tomorrow to wrap up the process.

When I have a chance will crack open the old rear diff to see what the issue is.

Thanks for all the help guys <img src="/forums/images/graemlins/cheers.gif" alt="" />

~ Jon