Noise Control System; Tampering With Noise Control System Prohibited - GMC 2007 Sierra Owner's Manual

If the level is below the bottom of the filler plug
hole, located on the front axle, you may need
to add some lubricant:
•
When the differential is cold, add enough
lubricant to raise the level from 0 (0 mm)
to 1/8 inch (3.2 mm) below the filler plug hole.
•
When the differential is at operating
temperature (warm), add enough lubricant to
raise the level to the bottom of the filler
plug hole.
What to Use
Refer to the Maintenance Schedule to determine
what kind of lubricant to use. See Recommended
Fluids and Lubricants on page 635.
542

Noise Control System

Tampering with Noise Control
System Prohibited
The following information relates to compliance
with federal noise emission standards for vehicles
with a Gross Vehicle Weight Rating (GVWR) of
more than 10,000 lbs (4 536 kg). The Maintenance
Schedule provides information on maintaining
the noise control system to minimize degradation
of the noise emission control system during
the life of your vehicle. The noise control system
warranty is given in your warranty booklet.
These standards apply only to vehicles sold in the
United States.