I have a binding or grinding coming from my front Diff or transfer case. It shakes the whole dash in the truck and sounds like something is trying to engage or disengage. It seems more on the right hand side....it makes the truck undriveable. Even happens in a straight line in 2wd (less than 5 MPH) and seems to only happen when going forward and not right from a takeoff, after driving 50 feet. The truck sat for a few months and I hap to put it in 4wd to get it out of where it was parked. Could this be an actuator or maybe a CV shaft (RH boot looks ripped)

 

grab ahold of the cv shaft and see if it has any slop, play, unnessesary movement, then just replace it anyway because you dont want it to go out when you need it the most

 

If the boot is torn you will need to replace it anyways as it will loose all of it's grease.