Mercedes Front Differential Removal Installation

A Mercedes front differential replacement at the dealer runs roughly $4,000 to $5,500, which is why a rebuild or a warrantied used unit is worth pricing first. The unit is fitted to 4MATIC models, and getting it out begins with dropping the soundproofing shield from under the car.

To remove the front differential from the car, you must remove the front passenger drive shaft. Plan on two hours to remove the differential from the car.

It takes one to two hours to rebuild the differential, and it will take about two hours to install it. Thus, the total time to change the Mercedes-Benz front differential is about 5 to 6 hours.

Signs the Front Differential Is Failing

• A whine or howl from the front that rises and falls with speed, often louder when accelerating or coasting.
• A clunk when pulling away or shifting between drive and reverse.
• Gear oil leaking from the differential seals or the axle seals.
• Vibration that you can feel through the floor at highway speed.

Before you remove it, rule out the easier causes. A worn front wheel bearing or a failing CV axle can sound very similar. Raise the front, spin each wheel by hand and listen, and check the differential fluid level and condition; metal flakes or a burnt smell point to internal wear.

Safety First

• Support the car on rated jack stands on solid ground, never on a jack alone.
• The differential is heavy; support it with a transmission jack or a helper before removing the last bolts.
• If you disconnect the brake line, bleed the brakes and confirm a firm pedal before driving.
• Have the alignment checked after the job if you separated the control arms or tie rod.

How to change the Mercedes-Benz front differential

The first step is to raise your vehicle. Raise your Mercedes-Benz and support it with jack stands.

Place wheel chocks on the back of the rear wheels to prevent the vehicle from rolling back. Make sure the car is in Park and the parking brake is applied.

1. Jack up the car. Ideally, use a garage lift or portable vehicle lift. If a lift is unavailable, jack up the vehicle and support it properly. It is important to secure the vehicle using two methods and ensuring the rear wheels are blocked with a wheel chock or block to prevent the vehicle from rolling back.
2. Remove the soundproofing shield from under the vehicle. Remove both front and back soundproofing. They are held in place with several 8mm bolts that must be removed.
3. Next, we need to disconnect the propeller shaft from the front differential. To do this, use an 8mm Allen socket and extensions to remove all six bolts.
4. Press the drive shaft towards the back of the vehicle, including the front joint. The driveshaft should shrink, allowing you to move it to the side. It is not necessary to disconnect the driveshaft from the transfer case.
5. Next, you need to remove the passenger-side driveshaft. There are two ways to do this. In this case, we disconnected the brake line, upper control arm, lower control arm, and tie rod and completely removed the wheel and steering knuckle. This method requires that you bleed the brake line afterward.
   The alternative method is to disconnect the upper and lower control arms, but instead of removing the whole steering knuckle, you pull out the CV joint and the half-shaft. The bottom line is that the drive axle assembly on the passenger side needs to be pulled out of the front differential.
6. Next, we need to disconnect the driver-side CV axle. It is unnecessary to remove the wheel on the driver’s side completely. Just remove the nut to the upper control arm.Next, unclip the brake hose and unhook the brake wear sensor from the retainers. This will allow you to swing out the steering knuckle, which provides enough room to pull the driver-side axle from the front differential.
7. Use a flat-head screwdriver to pry out the CV joints from the front differential.
8. Next, remove the bolts securing the front differential to the carrier. Before you remove the bolts, you either need to support the differential or have a second person help you by holding it up. 
9. Remove the differential from the vehicle.
10. Installation is in reverse. Tighten the propeller shaft to differential bolts to the torque and angle given in the service manual for your model. These are typically single use stretch bolts, so fit new ones rather than reusing the old set. 

Replacing the differential at the dealer can cost $4000 to $5500. That’s because dealerships don’t repair differentials; they replace them.

If you are on a tight budget, one way to save money is to buy a used Mercedes front differential with a warranty and install it yourself. The downside of this method is that you typically don’t know how long the used differential will last.

Frequently Asked Questions

How much does it cost to replace a Mercedes front differential?

A dealer replacement often runs 4,000 to 5,500 dollars. A rebuild with new bearings, or a used unit with a warranty, usually costs far less if you do the labor yourself.

Can I drive with a noisy front differential?

For a short time, but the noise usually gets worse and a seized differential can damage the transfer case or other drivetrain parts. Have it checked soon.

What fluid goes in the front differential?

Use the gear oil that meets the Mercedes specification for your model and differential, listed in the service information. Do not mix it with transmission fluid.

Do I need to bleed the brakes after this job?

Only if you disconnected the brake line to remove the steering knuckle. The alternative method in this guide avoids opening the brake system.

Check these troubleshooting and repair guides for more help on your Mercedes-Benz.

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