Ring and Pinion

I have a 1999 Chevy Silverado, and the front differential is making the much dreaded sound of a bad ring and pinion, I have yet to crack oppen the diff, but what else will probably be in need of replacing when I have the differential out?

I hear the clutch pack on the auto track transfer case will need checking to see how the clutch pack is holding up due to the worn ring and pinion.

Are there any bearings that are known to pitt or wear out? How about seals? Carrier? Spider gears? Anything I am missing that is a known weak spot?

Thanks, Steve