Noise in the front end! any ideas?

Just replaced all 4 ball joints. they had seen better days. I was hoping that this was going to fix the banging and rattling noise in the front end. I thought it might be the sway bar because it makes noise only when one wheel hits a bump.if both wheels hit a bump at the same time there is no noise. I have checked the sway bar bushings and the end links. I did noticed the the axle seemed to move around a bit. where it come out of the axle housing and goes into the hub. is it possible that the small needle bearing is no good? any in put would be helpful. I just bought this truck in June. I'm not sure of its' history. It is a 03 Excursion 4x4. :toytruck