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# SB-09271C.
Affected Component: POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM)
PONTIAC/SATURN/BUICK/GMC/CHEVROLET: TRANSMISSION CALIBRATION UPDATE. A SERVICE PROCEDURE TO REPROGRAM THE ECM AND TCM ON CERTAIN MODEL VEHICLES. THIS NEW CALIBRATION WILL IMPROVE TRANSMISSION SHIFT CHARACTERISTICS FOR DOWNSHIFT HESITATION, DELAYED SHIFTING, AND SHIFTING AT THE WRONG TIME. *PE