For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

California Proposition 65 WarningLockout Protection
If the driver side power door lock switch is pressed when the driver door is
open and the key is in the ignition, all of the doors will lock and then the driver
door will unlock.
If Unlocked Door Anti Lockout is turned on and: the vehicle is off, the driver
door is open, and door locking is r ...
Cylinder Head Cleaning and Inspection
Valve Cleaning and Inspection
Warning: Bodily injury may occur if the cleaning solvent is
inhaled or exposed to the skin.
Note: Do not scratch the valve stem with the wire brush.
Clean the valves of carbon, oil and varnish. Carbon can be remove ...
Automatic Transmission Flex Plate Installation
Special Tools
EN-652 Automatic Transmission Flex Plate Holder
For equivalent regional tools, refer to Special Tools.
Clean the automatic transmission flex plate bolt threads.
Install the automatic transmission flex plate (2) and
the EN-652 holder to hold the automatic tran ...