Mercedes-Benz Rear Differential Fluid Change (DIY)

Last updated: October 28, 2026

Rear Differential Problems and Symptoms

This DIY guide shows you how to replace the rear differential fluid in a Mercedes-Benz. Changing the differential fluid will help avoid costly differential repairs down the road. Some symptoms of a bad differential on a Mercedes-Benz are whining, rumbling, humming, growling, noise while turning, vibration, loud clanking, or grinding at low speeds. These symptoms can be noticed under stress, at high speed, or when taking a corner. A fluid change may be appropriate maintenance, but replacing the fluid will not repair damaged gears, bearings, seals, or differential components. Persistent whining, grinding, rumbling, or clunking should be diagnosed before assuming the fluid is the cause.

A lack of differential fluid can cause these problems. Differential-fluid service intervals vary by model, axle, operating conditions, and maintenance schedule. Follow the interval specified for your vehicle.

You can replace the differential fluid for under $50 if you purchase oil and tools online. Links are provided below. This is an easy task that you can tackle yourself. It’s not any more difficult than replacing the engine oil. To complete this job, you must have the correct oil screw wrench and oil transfer pump. On 4MATIC vehicles, the rear differential, front differential, and transfer case are separate components and may require different fluids, capacities, and procedures; our guide to rebuilding a Mercedes front differential covers the front unit. This guide covers only the rear differential unless otherwise specified.

Required Parts & Tools

Here is a list of the parts and tools needed to perform the rear differential fluid change on a Mercedes-Benz.

• Mercedes Differential Oil 75W85 (1 Liter)
• Drain Plug Wrench for Mercedes-Benz
• Drain Screw Plug Part Number: A 352 997 00 32

Use only the rear-axle gear oil specification specified for your vehicle/differential. Many Mercedes-Benz rear differentials use MB 235.7/235.74 75W-85, but some applications, including certain AMG and limited-slip differentials, require a different Mercedes-Benz approved specification. Do not substitute rear-axle fluid based only on viscosity; verify the required specification by VIN and rear-axle type before purchasing fluid. Differential capacity varies by chassis, axle housing, and differential type. Check the vehicle-specific service information for the correct capacity. Have enough fluid available to complete the fill procedure rather than relying on a universal 1-liter quantity.

How to Change Mercedes-Benz Rear Differential Fluid

Safely jack up your Mercedes-Benz

Raise and support the vehicle using the manufacturer’s specified lifting/support points. If the differential must be filled to the opening level, ensure the vehicle is positioned level as required by the service procedure. Do not use the jack to keep the vehicle off the ground. Always use jack stands.

Locate Rear Differential

Locate the rear differential at the rear of the vehicle.

Oil Drain Screw

Locate the oil drain screw at the bottom of the rear axle assembly. Remove the screw. Use the Mercedes-Benz Fluid Drain Wrench Tool listed under the parts section above to remove the screw.

Drain Oil

Drain the differential oil. If the car was in use right before you started to change the differential oil, be careful, as the fluid may be hot.

Oil Filler Screw

Locate the oil filler screw. It should be above the oil drain screw you removed in the previous step. Remove this screw. Inspect the drained fluid and the drain-plug magnet, if equipped, for excessive metallic particles or large metal fragments. A small amount of fine metallic paste may be normal on a magnetic plug, but significant chips or large fragments warrant further differential inspection. Wait for the differential fluid to completely drain via the bottom oil drain screw and install the oil drain screw back on. Drain/fill plug and sealing-ring part numbers vary by differential and chassis. Verify the correct part number by VIN or vehicle-specific parts catalog. Use the torque specification for your specific rear axle and replace the sealing ring if required. Replace the fill/drain plug sealing rings or washers if specified for your application. Do not reuse damaged sealing hardware.

Mercedes-Benz-approved hypoid gear oil for the rear differential

You will need approximately 1 liter of hypoid rear axle gear oil, SAE 75W-85. To check the exact capacity of your car, look it up in the owner’s manual specifications section. In this case, we used Mercedes part number 001 989 33 03 12 (MB 235.7).

Fill Differential

Clean the area around the fill and drain plugs before removing them to prevent dirt from entering the differential. Use an oil pump such as the Plews Lubrimatic Fluid Quart Pump to transfer the new oil into the rear differential via the oil fill screw. You will know when the differential is full when the oil starts to spill out of the oil fill screw. The vehicle must be positioned level when setting the final differential-fluid level unless the manufacturer specifies another procedure. Support the vehicle securely at appropriate lifting/support points.

Video: How To Change The Differential Fluid On Your Mercedes-Benz

On a 4MATIC car, the front differential is serviced separately:

Common Mercedes-Benz Differential Problems

Problem	Cause
Whirring noise when decelerating.	Bad pinion bearing. Loose pinion bearing preload.
Whine or how during acceleration.	Worn ring or pinion gears.
It was rumbling when driving at over 20 mph.	Worn carrier bearings.
Clunking at low speeds.	Possible broken ring or pinion gears.
Clunking during cornering and turning.	Possible causes include incorrect/low fluid level, worn internal components, bearing damage, or clutch-pack problems on applicable limited-slip differentials.

Rule Out the Sensors Before Blaming the Differential

Differential noise does not set a fault code, but the same hum or growl comes from a worn wheel bearing, and a failing bearing often damages the ABS wheel speed sensor next to it. A Mercedes capable scanner such as the UCAN-II Pro reads the ABS and ESP modules and shows each wheel speed live, so a sensor or bearing fault turns up before you drain the differential. Our guide to replacing a front ABS wheel sensor covers the most common one.

More How-To DIY Differential Oil Change Guides

Here is a list of other guides on how to replace the differential oil fluid on a Mercedes-Benz. These are links to external sites not owned by MercedesMedic.com.

• Mercedes Rear Differential Fluid Change Older Mercedes-Benz with Pictures
• Differential Oil Change on E Class W210 by Pelican Parts
• Photo DIY Rear Differential Oil Change by G-AMG member on BenzWorld.
• DIY 4Matic Front Differential Oil Change
• Differential Oil Change Mercedes R129
• How To Change Differential Oil in Mercedes-Benz

Mercedes-Benz Gear Oil Specifications

Mercedes-Benz operating fluids specifications (the official list that replaced the old BeVo pages)

The gear oils are approved for MB vehicles

Hypoid gear oils sheet 235.0/.6/.7/.8/.9/.15/.16/.17/.20/.31/.61/.62

Applicable Models

A-CLASS B-CLASS C-CLASS C Class Sedan C Class Wagon CL-CLASS CLK-CLASS CLS-CLASS E-CLASS G-CLASS GL-CLASS GLK-CLASS M-CLASS S-CLASS SL-CLASS SLK-CLASS SLR MCLAREN SLS AMG SPRINTER 

Rear differential design, fluid specification, capacity, plug type, and service procedure vary by chassis, axle housing, drivetrain, and differential type. Verify the procedure and fluid specification for your specific vehicle before servicing.

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