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 WarningFront Seat Outboard Seat Back Airbag Replacement
Front Seat Outboard Seat Back Airbag Replacement
Callout
Component Name
Warning: Following the deployment of a side impact air bag,
inspect the following parts for damage. Replace these parts if necessary:
...
Steering Gear Replacement
Steering Gear Replacement
Callout
Component Name
Caution: With wheels of the vehicle facing straight ahead,
secure the steering wheel utilizing steering column anti-rotation pin,
steering column lock, or a strap to p ...
Park - Engine Running (Gen 2)
When the gear selector lever is in the Park (P) position, fluid is drawn into
the pump through the transmission fluid filter assembly. Line pressure is then directed
to the following valves:
Fluid Pressure Directed in Preparation
for a Shift
Manual Valve
Mechanically controlled ...