2002 Ford Expedition • 121,500 miles

Help! 02 expedition awd 121xxx miles. I have had it aligned twice changed wheels balanced tires tires rotated, and it still has a wobble. Though maybe it was awd system but still does it coasting down a hill. Oh and new rear shocks. Tires seem to keep wearing weird, on the inside of rear one so bad it created a bubble and blew. The only other thing I have noticed is there is a popping sound when I turn wheel to left at slow speeds. I don't want to keep changing tired or wobble down to road anymore. Any ideas what to look for?
June 22, 2012.

I would check front hub bearing assemblies and the front axles.

Jun 22, 2012.