If you have an optional air-shift two-speed, controlled traction, or locking differential type rear axle, a good time to check the fluid level in the axle shift motor is when the rear axle lubricant is checked.
Remove the plug on the front plate of the axle shift motor, add enough fluid to raise the level to the bottom of the filler plug hole, then replace the plug.
Refer to your Maintenance Schedule to determine what kind of lubricant to use. See Part C: Recommended Fluids and Lubricants .