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 WarningOutside Rearview Mirror Housing Rear Cover Replacement
Outside Rearview Mirror Housing Rear Cover Replacement
Callout
Component Name
Preliminary Procedures
Remove the outside rearview mirror glass. Refer to Outside Rearview Mirror
Glass Replacement.
1
...
Driver or Passenger Seat Head Restraint Guide Replacement
Driver or Passenger Seat Head Restraint Guide Replacement
Callout
Component Name
Preliminary Procedure
Remove the seat head restraint. Refer to Driver or Passenger Seat Head
Restraint Replacement.
1
...
Special Tools
Illustration
Tool Number / Description
CH?E9376
Holding Wrench
CH?E9400
J-45859
Hub Spindle Remover
DT-6332
Seal Protector
DT- ...