Hi all. I have a 2000 Ford Lariat 4X4 F150 (75K miles) and once in a while whenever I turn the rear makes a popping noise. Almost sounds like something is rolling around in the bed of the truck. Just last week I replaced the U joints (both front and back). Any suggestions?

 

Could be a busted tooth on an axle gear or broken brake parts on the rear wheel. If you ever had an axle seal go bad - they could have dropped a part in the axle case and left it (common).

 

I would check the crossmember and make sure the ball joints in the front are still solid