Ever sense I purchased this 1997 Jeep Cherokee XJ back in late April 2011 there has been an intermittent clunking noise when engaged in either 4-high or 4-low. It only happens when accelerating in a "jerking" way. It seems to happen more when climbing and/or the wheels are turned making the acceleration more jerky. I finally crawled under it today and found that all the u-joints seem perfectly fine but when the front wheels are held still and I twist the front drive shaft back and forth it sounds like the clunking is coming from inside the front differential (which is a Dana 30). I also think I can feel slight metal on metal rubbing in the front diff from twisting the front drive shaft back and forth. Does anyone know what this might be or how to figure it out/fix it. If not I guess the next step would be to take the front diff apart? Any advise helps greatly!