Ok...has anybody experienced this yet, by the way i have a 05 ss s/c if this may help..but whenever i get on it WOT like in a race or such... the rear end has a clunking sound that sounds like it may be with the axel or something. it thuds with the revolution of the tires and axel. i know it's not my rims there aren't any cracks or flat spots. and i havent done anything to cause this. as im comming down from high the high rpm's from the race i can hear it and feel it.then it goes away about two minutes later.this happend about 3 times now over 7months,not that frequent and it's annoying as hell clunk clunk then it goes away, but how do i tell the dealer that it only happens everyonce in a while when i get on it. then they'd really beat the hell out of it trying to find the problem... . any ideas???

 

We've had a few cobalts in the shop that come in complaining of a clunking coming from the rear at high way speeds, and it turned out to be a halfshaft (front axle). Take it into the dealer and have them check it out.