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 WarningStarting System Description and Operation
The starter motors are non-repairable starter motors. They have pole pieces that
are arranged around the armature. Both solenoid windings are energized. The pull-in
winding circuit is completed to the ground through the starter motor. The windings
work together magnetically to pull and hold in ...
Heater Inlet Hose Replacement (LUV)
Heater Inlet Hose Replacement
Callout
Component Name
Preliminary Procedures
Drain the engine coolant. Refer to Cooling System Draining and Filling.
Remove the charge air cooler outlet hose. Refer to Charge Air Cooler
...
Control Solenoid Valve and Transmission Control Module Assembly Programming
and Setup (6T30/6T40/6T45/6T50)
The following service procedures require either a programming or a setup event
be performed for a complete repair. The transmission control module (TCM) is part
of the control solenoid valve assembly, and is not serviced separately.
Transmission Control Module (TCM)
Replaceme ...