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# 831220.
A/C COMPRESSOR CLUTCH IS ENGAGED. THIS CONDITION IS MOST NOTICEABLE WHEN ENGINE IS AROUND THE 1000-2000 RPM RANGE. THE NOISE MAY BE LODEST WHEN THE ENGINE IS UNDER LIGHT ACCELERATION THROUGH THIS RPM RANGE. THE MOAN NOISE MAY BE CREATED BY COMPRESSOR PULSES WHICH SET UP A SYSTEM RESONANCE BETWEEN THE COMPRESSOR AND THE IN-LINE MUFFLER.
