my BMW 5 Series has a whining noise from the differential what's wrong

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is on a level surface and secure it using jack stands.
• Disconnect the battery to prevent any electrical issues during the repair.

2. Drain the Differential Fluid

• Remove the drain plug from the differential using a socket set.
• Allow the fluid to fully drain into a suitable container.
• Inspect the drained fluid for metal shavings or debris.

3. Inspect and Replace Bearings (if necessary)

• Remove the differential cover by unbolting it with a socket set.
• Inspect the ring and pinion gears for wear or damage.
• If bearings are worn, remove the differential assembly and replace with new bearings.
  • Use a bearing puller for removal.
  • Install new bearings using a press and ensure they are properly seated.

4. Clean and Reassemble

• Clean the differential housing and cover with a solvent.
• Replace the gasket or use RTV sealant as appropriate.
• Reinstall the differential cover and torque bolts to manufacturer specifications (usually around 30-40 Nm).

5. Refill Differential Fluid

• Replace the drain plug after ensuring it is clean and free from debris.
• Refill the differential with the appropriate fluid type, typically 75W-90 gear oil.
• Use a fluid pump to ensure proper filling to the recommended level.