Sierra Classic 2500 4WD V8-8.1L (2007)
2. Fill the transfer case to the bottom of the fill plug hole with Auto-Trak II, transfer case fluid, GM P/N 12378508 (Canadian P/N 10953626).
3. Install the fill plug.
Tighten the plug to 20 Nm (15 ft. lbs.).
4. Install the transfer case shield, if equipped. Refer to Transfer Case Shield Replacement.
5. Lower the vehicle.