What should I do if my 2020 Toyota Highlander experiences transmission slippage?

If your 2020 Toyota Highlander is experiencing transmission slippage, it's essential to address the issue promptly to avoid further damage. Below are detailed diagnostic steps and repair instructions.

Tools Required

• OBD-II scanner
• Transmission fluid dipstick (if applicable)
• Transmission funnel and Toyota WS transmission fluid
• Socket set and ratchet
• Torque wrench
• Multimeter (for electrical testing)
• Screwdrivers
• Safety gloves and goggles

Repair Instructions

Step 1: Top Up or Replace Transmission Fluid

1. Locate the Transmission Fill Plug:

   • For the Highlander, the fill plug is typically found on the side of the transmission case.

2. Check Fluid Level:

   • Remove the fill plug and insert a clean dipstick or finger to check the fluid level.

3. Top Up Fluid:

   • If low, use a funnel to add the appropriate amount of Toyota WS transmission fluid.

4. Replace Fluid (if necessary):

   • If the fluid is burnt, perform a fluid change:
     • Drain the old fluid by removing the drain plug.
     • Replace the filter if equipped (consult the service manual).
     • Refill with new Toyota WS fluid through the fill plug.

Step 2: Inspect and Replace Transmission Range Sensor

1. Disconnect Battery:

   • Disconnect the negative terminal of the battery for safety.

2. Locate the Sensor:

   • The transmission range sensor is typically mounted on the transmission housing.

3. Remove the Sensor:

   • Unplug the electrical connector and remove the mounting bolts.
   • Carefully remove the sensor from the transmission.

4. Install New Sensor:

   • Install the new sensor, ensuring it aligns correctly.
   • Reconnect the electrical connector and secure the mounting bolts.

5. Reconnect Battery:

   • Reconnect the negative terminal of the battery.

Step 3: Perform a Test Drive

1. Monitor Behavior:

   • After repairs, take the vehicle for a test drive to ensure the slippage issue has been resolved.
   • Check for any warning lights on the dashboard.

2. Recheck Fluid Level:

   • After the test drive, recheck the transmission fluid level and top up if necessary.

Conclusion

If the slippage persists after following these steps, it may indicate a more serious issue such as internal transmission failure, which may require professional diagnosis and repair. It's advisable to consult a certified Toyota technician for further inspection.