HOw often does the lube (differential?) need to be changed? I usually change oil and filter myself, but it occasionally goes to the mechanic for routine check up and tune-up. I know they do new lube at that time, but is it ok that I don't do the lube at my oil changes? Is this ok? What is the lube for exactly? How difficult is it to change for an avg. DIYer?

Check owners manual. If the rear end has not been opened up or worked on, check the level by removing the fill plug. Your vehicles are not really that old, but if you feel compulsive, you can certainly drain and change the diff lube. This is there to keep all the gears, bearings bushings happy and slick.. Not sure, but between 30,000 and 50,000 miles is an OK interval. But, again check your owners manual for specifics..

Hottee,

It is better for the differential to change the oil once to many...I change the oil of my differential (and manual transmission) every 50.000km (30.000miles).

It is easy to do it yourself as long as you have a your car lifted up. There are 2 plugs in the differential. The upper plug is to check the oil level and fill the differential. The lower plug is to let of the oil.

greetingz,

If you opt to change you gear oil in the rear diff, be sure to remove the fill plug (upper) first. Reason being, if the upper plug is stuck/stripped and you cannot remove it, but have already removed the drain plug (lower), you now have no way of replacing the oil. Very simple procedure:

Pull upper plug, position drain pan under the diff, pull lower plug. If the rear diff is warmed up, it will drain out in about a heartbeat or two. If stone cold, it may take a minute or so. Allow to drain as long as you can (an hour or more,even overnight [right Larry] if you're not in any hurry), then replace lower plug and top off with 2 quarts of your favorite hypoid gear oil.