Removal Procedure

Raise and support the vehicle.
Important: Do not remove the muffler.
Remove the fasteners that attach the muffler to the catalytic converter.
Reposition the muffler in order to access the heat shield rivets.
Use a drill in order to remove the heat shield rivets.
Remove the exhaust muffler heat shield from the vehicle.

Fig 1: Removing Fasteners That Attach Muffler To Catalytic Converter
Courtesy of GENERAL MOTORS CORP.