Explorer making noise when turning from a stop

[tuik]

My 2003 Explorer xlt 4x4 V6 makes a noise/rough feeling when I turn the wheel from a stop right and left while accelerating. It goes away after I begin to speed up and is gone until I have to stop and accelerate again. I have just changed the fluid in my rear differential and added the friction modifier. Seemed to fix the problem, but now it is doing it again. Does this mean I need to replace the clutch packs for certain? Or how do I know if this could be more work involved? I've never worked on a rear end before.

 

[Number4]

My dad just had this scenario happen. Took apart the rear diff and it had grenaded. Had to put in a completely new rear axle assembly.