No to long ago I started noticing that I was picking up a pretty nasty sounding metallic clunk when hitting some nice size bumps along with when I put it in reverse. So i get under the truck to check out the u-joints. Everything checks fine there but then I find a ton of play in the trasfer case slip yoke. Vertical, Horizontal, all kinds of movement, this has got to be where the noise is coming from, especially when hitting bumps under power as it throws the driveshaft around. Has anyone else had this problem? I got a warranty on the truck when I bought it used, I had already took it in once for the problem, they dicked around and changed the yoke going to the rear differential along with the u-joints, but never listened to me. So now its back there, just wondering if this is a common problem, as about a week ago i was following another 99-00 Silverado and heard a similar noise when he hit bumps.

 

I'm not sure what exactly it was, but I know there was a TSB on the slip yoke (not even sure what that is, but I remember what the recall was for), I had mine replaced awhile ago. I dunno any more details than that. Maybe worth checking out.

 

Change the slip yoke. It is made of a softer material than the output shaft and will usually wear first.