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:

Vehicle Care
California Proposition 65 WarningRemoval Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Collision Sectioning Warning in the Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Dis ...
Installation Procedure
Remove rear end upper panel extension (1) from service part.
Cut the body side inner panel in corresponding locations to fit the
remaining original panel. The sectioning joint should be trimmed to
allow a gap of one-and-one-half-times the metal thickness at the sectioning
jo ...
Hill and Mountain Roads
Driving on steep hills or through mountains is different than driving on flat
or rolling terrain. Tips for driving in these conditions include:
• Keep the vehicle serviced and in good shape.
• Check all fluid levels and brakes, tires, cooling system, and transmission.
• Shift to a lower g ...