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# PIP-4414A.
CHEVROLET/GMC: A WHINE, GRIND OR CLUNK NOISE FROM THE REAR AXLE AT SPEEDS ABOVE APPROXIMATELY 30 MPH (50KPH). THIS CONDITION ONLY APPLIES TO 10.5 REAR AXLE ASSEMBLIES, WHICH ARE USED ON 2500 AND 3500 SERIES PICKUPS EQUIPPED WITH A 5.0L ENGINE. *PE