2001 GMC Sierra Ex Cab Z71. When you come to a stop it makes a clunk or slap sound. Does same when you take off like it goes back into place. You can feel it to. Its almost like the whole rear end axle and all roll forward or something when you stop and it makes the noise and then it goes back when you take off. Any ideas? 208,000 miles on truck. Also on my rear brakes I think its coming from drivers side it has a rattle but when break is applied even just pushing the petal down a little it goes away. I cant target it for the life of me.