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 WarningInstrument Panel Airbag Arming Status Display Replacement
Instrument Panel Airbag Arming Status Display Replacement
Callout
Component Name
Preliminary Procedure
Remove the heater and air conditioning control. Refer to Heater and Air
Conditioning Control Replacement.
...
Warm Up Three-Way Catalytic Converter Removal
Disconnect the heated oxygen sensor wiring harness (3) from retainer clip.
Remove the 2 catalytic converter to catalytic converter bracket nuts (4)
and (6).
Loosen the three way warm up catalytic converter V-clamp (1).
Remove the three way warm up ...
Oil Pump Cleaning and Inspection
Remove the external rotor with the internal rotor.
Visually inspect the components.
Install the external and the internal rotors.
Inspect the axial clearance of the rotors in respect to the control unit
housing upper edge.
Specifications
Permissible measurement is 0.02?E.058 ...