my BMW X3 F25 (2011-2018) rear differential is making noise, what's wrong

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a level surface and securely lifted on jack stands.
• Disconnect the battery to prevent electrical issues.

2. Drain Differential Fluid

• Place a drain pan under the differential.
• Remove the drain plug and allow the fluid to completely drain.
• Inspect the fluid for metal shavings or debris indicating wear.

3. Remove Differential Cover

• Remove the bolts securing the differential cover using a socket set.
• Carefully pry off the cover, ensuring not to damage the gasket surface.
• Inspect the interior for wear, broken gears, or damaged bearings.

4. Replace Worn Components

• If any gears, bearings, or seals are damaged, replace them with OEM or quality aftermarket parts.
• Clean the mating surfaces of the differential and cover thoroughly.

5. Reassemble Differential

• Apply a new gasket or silicone sealant to the differential cover.
• Reattach the cover and torque the bolts to the manufacturer’s specifications (typically around 30 Nm).
• Replace the drain plug and torque to specifications.

6. Refill Differential Fluid

• Fill the differential with the appropriate fluid (usually a synthetic gear oil, consult the owner's manual for specifications).
• Ensure fluid is filled to the proper level, typically until it begins to seep from the fill hole.

7. Test and Monitor

• Reconnect the battery.
• Start the vehicle and listen for abnormal noises.
• Test drive to ensure the noise has been resolved.