Sprinter Rear Differential Noise & Axle Shaft Failure: The "Knocking" Warning You Can't Ignore

Here is the hard truth: If you hear that knock, your rear axle shafts may be in the final stages of failure. If you ignore it, the result is 100% guaranteed: one day soon, you will press the gas, the engine will rev, the driveshaft will spin, but your van will not move.

At Sprinter Van Solutions, we see this issue constantly. Here is what is happening inside your rear differential and why you need to fix it before you need a tow truck.

Take a look at these photos from a Sprinter we recently serviced in our Miramar shop.

Your Mercedes Sprinter uses axle shafts with splines (teeth) that slot into the wheel hub to turn the wheels. Over time, due to lack of lubrication or water intrusion, these splines begin to rust.

As the rust eats away at the metal, the fit becomes loose. That looseness causes the "knocking" sound. Eventually, the teeth strip completely smooth (like a stripped screw head). When that happens, the axle spins freely inside the hub, and the wheels get zero power.