Sorry, the NHTSA has not posted this TSB document yet.
You can still get the detailed info from Chevrolet for this TSB. Call your local Chevrolet dealer's service department & ask for a copy of TSB# 09-04-21-003D.
GM: WHEN STOPPING OR ACCELERATING THERE MAY BE A CLUNK NOISE AND ITS AS IF THE VEHICLE IS BUMPED FROM BEHIND. THIS CAN BE CAUSED BY A SLIP IN THE REAR PROPSHAFT. *RM