And if not BJ's rock in the hubcap then probably your CV joint going south. Look at the rubber boots and see if they're still intact. If they're split all the grease could be gone. Not too difficult to replace the boots and repack with grease if the joint's not too far gone yet.

97tj, Shaved Ford 9 rear, 4:10's, New 35x12.5 BFG KM2's to test!, Warn x8000i, ARB's, Quick Disco's, Hand Throttle, & it's my DD. smile