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-3366-B.
Affected Component: POWER TRAIN:AUTOMATIC TRANSMISSION
CADILLAC/CHEVROLET/GMC/HUMMER: SOME SUVS AND TRUCKS ARE EXHIBITING A CONDITION WHERE BY GRINDING/RATCHETING TYPE NOISE COMING FROM AUTOMATIC TRANSMISSION WHEN SHIFTING INTO PARK WHILE IN 4WD LOW (4LO) RANGE. *PE