my BMW X3 G01 (2018-2024) is not shifting gears smoothly, what's wrong?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, transmission fluid pump, fluid catch pan.
• Ensure the vehicle is on a level surface and the engine is off.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Check and Replace Transmission Fluid

• Fluid Inspection:
  • Remove the transmission dipstick and check fluid level and condition.
  • If the fluid is low or burnt, proceed to replace it.
• Fluid Replacement:
  • Place a fluid catch pan under the transmission pan.
  • Remove the transmission pan bolts and carefully detach the pan.
  • Replace the transmission filter if applicable.
  • Reinstall the transmission pan with a new gasket, tightening bolts to the manufacturer’s torque specifications.
  • Use a transmission fluid pump to add the correct type and amount of transmission fluid through the dipstick tube.

3. Inspect and Repair Wiring and Connectors

• Inspect the TCM connectors for any signs of corrosion or damage.
• Clean or replace any faulty connectors and ensure they are securely attached.

4. Reprogram Transmission Control Module (if necessary)

• If error codes indicate TCM issues, reprogram the TCM using a compatible diagnostic tool.
• Follow the manufacturer's procedure for TCM reprogramming.

5. Reconnect Battery and Test Drive

• Reconnect the negative battery terminal.
• Start the vehicle and take it for a test drive to evaluate shifting performance.