my BMW 5 Series G30/G31 (2017-2024) transmission fluid is leaking, what should I do?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface with the engine off and cool.
• Disconnect the battery to avoid electrical issues.

2. Identify the Source of the Leak

• Raise the vehicle using a jack and secure it with jack stands.
• Remove the underbody cover if present to access the transmission.
• Clean the area around the suspected leak source with a degreaser.

3. Replace Damaged Seals or Gaskets

• Transmission Pan Gasket:

  • Remove the transmission pan bolts using a socket set.
  • Carefully lower the pan and remove the old gasket.
  • Clean the pan and transmission mating surfaces thoroughly.
  • Install a new gasket and reattach the pan, torquing the bolts to the manufacturer’s specification (typically 8-10 Nm).

• Input/Output Shaft Seals:

  • Remove the driveshaft (if necessary) to access the output shaft seal.
  • Use a seal puller to remove the old seal.
  • Lubricate the new seal's edge with transmission fluid and install it using a seal installer tool.

4. Refill Transmission Fluid

• Locate the fill plug on the transmission.
• Use a funnel to refill with the correct type of transmission fluid, as specified in the owner's manual.
• Check the fluid level again using the dipstick and adjust as necessary.

5. Final Assembly and Testing

• Reinstall any components removed during the process, ensuring all connections are secure.
• Reconnect the battery and start the engine.
• Allow the transmission to warm up while checking for leaks and verifying fluid level.