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 WarningBrake Fluid
The brake/clutch master cylinder reservoir is filled with DOT 3 brake fluid as
indicated on the reservoir cap. See Engine Compartment Overview for
the location of the reservoir.
There are only two reasons why the fluid level in the reservoir might go down:
The fluid level goes down ...
Rear Spring, Insulator, and Jounce Bumper Replacement
Rear Spring, Insulator, and Jounce Bumper Replacement
Callout
Component Name
Preliminary Procedure
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
1
Rear Spring
Proced ...
Drive Range, First Gear Engine Braking (Gen 1)
When the gear selector lever is moved to the Drive (D) range from the Neutral
(N) position, the transmission will provide engine braking. In this operating range,
the normally-low 1234 pressure control solenoid 5 is commanded ON and, in the engine
braking mode, the following changes occur with ...