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 WarningInstallation Procedure
Note: If the location of the original plug weld holes can not be
determined, space the braze holes every 40 mm (1½ in).
Create 5 x 18 mm (4/16 x 11/16 in) slots for MIG-brazing along the edges
of the rear floor panel filler as noted from the original
panel.
Clean and prepare ...
Removal Procedure
Raise and support the vehicle. Refer to Lifting and Jacking the
Vehicle.
Remove the tire and wheel. Refer to Tire and Wheel Removal and
Installation.
Note: DO NOT re-use the lower control arm bolts and nuts. Discard
and use NEW only.
Remove wheel speed sensor wiring harness ...
Automatic Transmission Fluid
How to Check Automatic Transmission Fluid
It is not necessary to check the transmission fluid level.
A transmission fluid leak is the only reason for fluid loss. If a leak occurs,
take the vehicle to your dealer and have it repaired as soon as possible.
The vehicle is not equipped with a transm ...