I have a 2000 z71 that makes a noise that sounds like its slipping or a clunking noise when you mash the brakes. It has new rotors and pads and it does not do it every time. I need help if you have any ideas please respond. I am new here but hope to be around a while. I also have 2002 gran prix that will do it also but not as regular.

 

Doubt it is it but my 2011 was doing the same thing, ended up being the previous owner removed the nerf bars and didnt tighten the bolts. The dealer said the cab was moving away from the frame. ITs all tight now and no noise.

 

For the Z71 it is probably the slip yoke on the driveshaft needing grease. This is a very common problem.

 

mine does the same i actually greased it and now its back to doing the noise. so i suggest replacing them. i haven't gotten around to doing so but i will.