In this episode of Restore It, we document the restoration and rebuilding of the differential from the Mercedes W123 2180CE, ...

Learn how to maintain your car’s differential with this step-by-step guide. Avoid costly repairs by changing the differential oil and keeping your vehicle in top shape.

But if lubrication in the car differential fails, you won't be getting very far for very long. Fortunately, you only need to change this oil every 30,000 to 50,000 miles.

Another plus is if the differential has a drain plug. (Note: The fill plug is usually located about halfway up the side of the case, but the drain plug would be near the bottom.) ...

We started by opening up the oversized inspection/fill port on the AEV differential cover. See All 11 Photos Next, we removed the drain plug on the differential housing.

Fill and drain plugs have become standard fare on aftermarket covers, but Banks takes it a step further and adds a sight glass for easy fluid checks. Finishing off the package is a Viton O-ring ...

Using a square, we determine that the center of our new fill plug's hole should be 4 3/8 inches above the axle housing's low point. See All 25 Photos Back at our own shop, let's begin by locating ...