my BMW 5 Series transmission slips when shifting what could be wrong

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, transmission fluid pump, funnel, torque wrench, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface and the engine is off. Disconnect the battery.

2. Check and Replace Transmission Fluid

• Sub-steps:
  1. Remove the transmission fluid dipstick (if applicable) to check fluid level.
  2. If fluid is low, use a transmission fluid pump to add the recommended type of fluid (consult the owner's manual for specifications).
  3. If fluid is dirty or burnt, drain the transmission fluid by removing the transmission pan bolts.
  4. Replace the transmission filter while the pan is off. Clean the pan and replace the gasket.
  5. Reinstall the transmission pan with a torque wrench set to the manufacturer’s specifications.

3. Inspect and Replace Transmission Control Module (if necessary)

• Sub-steps:
  1. Disconnect the battery and remove any covers to access the TCM.
  2. Unplug the wiring harness from the TCM and remove the module.
  3. Install the new or reprogrammed TCM, ensuring all connectors are secure.
  4. Reconnect the battery and recheck for error codes.

4. Test Drive and Calibration

• Sub-steps:
  1. Start the engine and allow it to reach operating temperature.
  2. Perform a test drive to evaluate transmission performance.
  3. Use a diagnostic tool to check for any new error codes and ensure proper shifting patterns are established.