how to fix a slipping transmission in Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

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

2. Check and Replace Transmission Fluid

• Sub-steps:
  1. Remove the transmission dipstick and check fluid level; add fluid if low.
  2. If fluid is dark and smells burnt, drain the old fluid:
     • Place a pan under the transmission pan.
     • Remove the transmission pan bolts and carefully lower the pan.
  3. Allow old fluid to fully drain.
  4. Replace the transmission filter:
     • Remove the old filter and install the new one, ensuring it is seated properly.
  5. Reinstall the transmission pan with a new gasket and torque to manufacturer's specifications (typically 10-15 ft-lbs).

3. Inspect and Repair Transmission Components

• Sub-steps:
  1. Inspect the solenoids for proper operation:
     • Use a multimeter to test resistance; replace if out of spec.
  2. If slipping persists, consider replacing the transmission control module (TCM) if diagnostics indicate faults.
  3. If mechanical issues are suspected, prepare for a full transmission rebuild or replacement.

4. Refill Transmission Fluid

• Sub-steps:
  1. Refill the transmission with the correct type of fluid (typically Toyota ATF WS).
  2. Start the engine and allow it to reach operating temperature.
  3. Cycle through the gears to ensure fluid circulates properly.
  4. Check fluid level again and top off as necessary.