Ya its really easy, First take the cover off and let the oil drain in a pan, make sure that you remove all the gasket from the housing and the cover, now would be a great time to paint the cover just make sure you let the paint dry. Use RTV for the new gasket on the housing let it dry for only 5-10min and bolt the cover back on. The fill plug is on the drivers side front of the Dif housing you can use the 3/8" ratchet to remove the fill plug and add the new Diff oil I would use Royal Purple 75W140 its great stuff and its only $10qt you will need 4qts I believe. If you have any more question let us know.
~Gage~