At first I thought it was a U-joint or the carrier bearing, but a couple times when just getting into the truck, I hear this loud pop. I crawled under yesterday and noticed that the driver side cab mount looks a little funky and it made me wonder if that rubber being a little collapsed could let something move enough to make that popping sound. It sounds like a metal on metal pop to me. Anyone ever had anything comparable? Or should I just start replacing U-joints and posssibly the carrier bearing. They do all have some age and miles on them, so I'm thinking of just going through and changing them anyway. But the popping is making me scratch my head as to the cause. Thanks for any insights you guys might have, LB.