This has to do with the dust boot that covers the universal joint coming out of the transfer case. History: April 2009 took the truck in to have the front drive line inspected...noises. Determined that the left bearing and short shaft needed replacement. Also decided to have the front drive shaft rebuilt. The rebuild includes a new dust boot. The original boot was shredded...don't know for how long. Nine-ten months later I was under the car and noticed the new dust boot was torn again, slinging lube. Took it back in to the same shop and they sent it out to have it redone by the same guys. Altho out of warranty, the drive-line shop rebuilt it at no charge...nice guys! OK, so 3 months go by and I'm under the truck again and same thing...shredded dust boot! Damn! Back to the shop and the shop owner put his own same gen Ex on the lift to compare and what does he find? Right...a shredded boot on his own Ex rebuilt by the same drive-line shop! Needless to say, they're talking. Don't know where it's all gonna end up. Does anyone have a clue why this damage keeps recurring? I can only assume that they're doing a shaft balance, etc...I mean, they've been in business a long time...same location for lotsa years. Two trucks, same problem? Too weird!