Summary:
Often times front axle housings are filled with the same fluid that the transmission is. This is perfectly acceptable as a good quality fluid is used from the factory. When changing this oil consider upgrading to an 80W-90 weight oil. This is suited best for use in heavy duty gear boxes.
80W-90 Gear Lube
When draining this oil make sure that you check for multiple drain plugs, and when filling leave time for the oils to settle down into the lower regions of the gear boxes before topping it off.
