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 WarningTheft Deterrent Module Replacement
Theft Deterrent Module Replacement
Callout
Component Name
Preliminary Procedure
Remove the steering column upper trim cover. Refer
to Steering Column Upper Trim Cover Replacement.
Remove the steering column lower trim ...
Piston, Connecting Rod, and Bearing Installation
Special Tools
EN-470-B Angular Torque Wrench
For equivalent regional tools, refer to Special Tools.
Adjust the piston ring joints as follows:
Upper compression ring (1).
Lower compression ring (4).
Oil rings (2) or (3).
Oil ring spacer (5). ...
Control Solenoid Valve and Transmission Control Module Assembly Installation
Control Solenoid Valve and Transmission Control Module Assembly Installation
Callout
Component Name
1
Control Solenoid Valve Assembly Filter Plate
Caution: Use care when removing or installing the filter plate
...