What should I do if my 2020 Toyota Highlander’s transmission is slipping?

Toyota Highlander Fourth Generation (2020-present)

Error Codes

medium

Difficulty

high

Severity

4 min read

615 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and repair transmission slipping issues in your 2020 Toyota Highlander with our detailed guide on symptoms, diagnostic steps, and repair instructions.

Affected Component

transmission

Symptoms

•Unresponsive Acceleration
•Delayed Shifting
•Rough Shifting
•Warning Light
•Fluid Leaks

Diagnostic Steps

1
Check Transmission Fluid Level and Condition
2
Scan for Diagnostic Trouble Codes (DTCs)
3
Inspect for External Leaks
4
Test Drive the Vehicle

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•Transmission dipstick
•clean rag
•funnel
•OBD-II scanner
•flashlight
•inspection mirror
•transmission fluid (Toyota ATF WS)
•transmission fluid pump
•drain pan
•wrench set
•repair manual specific to the Highlander

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Solution

If your 2020 Toyota Highlander is experiencing transmission slipping, it’s important to address the issue promptly to avoid further damage. Below is a detailed guide outlining symptoms, diagnostic steps, tools required, and repair instructions.

1. Check Transmission Fluid Level and Condition

Tools Required: Transmission dipstick (if applicable), clean rag, funnel.
Instructions:
1. Start the engine and let it idle until warm.
2. With the vehicle in park, pull out the transmission dipstick.
3. Wipe the dipstick clean and reinsert it.
4. Remove the dipstick again and check the fluid level.
5. Evaluate the fluid condition; it should be bright red and clear. If it’s dark brown or smells burnt, it may need to be replaced.

2. Scan for Diagnostic Trouble Codes (DTCs)

Tools Required: OBD-II scanner.
Instructions:
1. Connect the OBD-II scanner to the vehicle’s diagnostic port (usually located under the dashboard).
2. Turn on the ignition (without starting the engine).
3. Use the scanner to read any trouble codes related to the transmission.
4. Document any codes for further analysis.

3. Inspect for External Leaks

Tools Required: Flashlight, inspection mirror.
Instructions:
1. Visually inspect the transmission casing and surrounding areas for signs of fluid leaks.
2. Use the flashlight and inspection mirror to check hard-to-see areas.

4. Test Drive the Vehicle

Instructions:
1. Take the vehicle for a test drive to replicate the slipping condition.
2. Pay attention to any unusual sounds, vibrations, or warning lights.

Repair Instructions

1. If Fluid is Low

Tools Required: Transmission fluid (Toyota ATF WS), funnel.
Instructions:
1. Add the appropriate transmission fluid through the dipstick tube using a funnel.
2. Recheck the fluid level to ensure it’s within the recommended range.

2. If Fluid is Contaminated

Tools Required: Transmission fluid pump, new transmission fluid, drain pan, wrench set.
Instructions:
1. Place a drain pan under the transmission pan.
2. Remove the transmission pan bolts using the wrench set.
3. Carefully lower the pan and allow the old fluid to drain completely.
4. Replace the transmission filter (if applicable) and gasket.
5. Reattach the transmission pan and refill with new fluid.
6. Start the engine and cycle through the gears to circulate the new fluid.

3. If DTCs Indicate a Specific Issue

Tools Required: Repair manual specific to the Highlander, additional diagnostic tools as needed.
Instructions:
1. Refer to the repair manual for the specific codes retrieved.
2. Follow the troubleshooting steps outlined for those codes, which may involve checking solenoids, wiring, or other components.
3. Repair or replace any faulty components as indicated.

4. If No Obvious Fluid Issues

Instructions:
1. If no fluid issues are found, further diagnosis may be needed, which could involve testing the transmission control module (TCM) or inspecting internal components.
2. Consult a professional if the issue persists, as internal transmission repairs can be complex.

Conclusion

If the transmission continues to slip after checking and addressing fluid levels and conditions, or if you are unsure about performing any of these steps, it is recommended to take your vehicle to a certified Toyota technician for further diagnosis and repair. Early intervention can save you from more costly repairs down the line.