why is my BMW 3 Series E90/E91 (2005-2012) transmission slipping during acceleration

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a level surface and safely elevated using jack stands.
• Disconnect the battery to prevent electrical shorts.

2. Check and Replace Transmission Fluid

• Sub-steps:
  • Locate the transmission fluid dipstick or fill plug.
  • Remove the dipstick or fill plug and check fluid level.
  • If low, add the correct type of ATF (refer to the owner's manual for specifications).
  • If the fluid is dirty or has a burnt smell, drain the old fluid.
  • Replace the transmission fluid with new fluid using a pump or funnel.
  • Reinstall the dipstick or fill plug securely.
• Tools Required: Fluid pump, funnel, socket set.
• Safety Warnings: Ensure the engine is cool before draining fluid to avoid burns.

3. Inspect and Replace Transmission Filter

• Sub-steps:
  • Remove the transmission pan using a socket set, ensuring to catch any remaining fluid.
  • Inspect the filter for clogs and replace it if necessary.
  • Clean the transmission pan and magnet, removing any debris.
  • Reinstall the transmission pan with a new gasket, tightening bolts to the manufacturer's torque specifications.
• Tools Required: Socket set, torque wrench, gasket scraper.
• Safety Warnings: Use gloves to protect from sharp edges and hot components.

4. Check Transmission Control Module (TCM)

• Sub-steps:
  • Inspect the wiring harness connected to the TCM for any damage or corrosion.
  • If available, reprogram or update the TCM using appropriate software.
  • Test the TCM operation using a scan tool to ensure it is communicating properly with the transmission.
• Tools Required: OBD-II scanner, multimeter.
• Safety Warnings: Disconnect battery before working on electrical components.