See also:

When to Check and Change Lubricant
It is not necessary to regularly check front axle fluid unless a leak is suspected, or an unusual noise is heard. A fluid loss could indicate a problem. Have it inspected and repaired. ...

Range Selection Mode (Allison® Transmission or Hydra-Matic® 6-Speed Transmission)
The vehicle may have a Range Selection Mode. The Range Selection Mode helps control the vehicle's transmission and vehicle speed while driving down hill or towing a trailer by letting you select a d ...

Engine Hour Meter Display
The Driver Information Center (DIC) can also display the number of hours the engine has run. To display the engine hours, turn the ignition off, then press and hold the reset button for at least four ...