What should I check if my 2020 Toyota Highlander has a rough transmission shift?

Toyota Highlander Fourth Generation (2020-present)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

4 min read

721 words

Problem Statement

Learn how to diagnose and fix rough transmission shifts in your 2020 Toyota Highlander with step-by-step instructions and required tools.

Affected Component

Transmission

Estimated Time

2-4 hours

Symptoms

•The vehicle hesitates or jerks during gear changes.
•Delayed engagement when shifting from Park to Drive or Reverse.
•Unusual noises (grinding, whining) during shifting.
•Check Engine light may be illuminated.

Diagnostic Steps

1
Observe the behavior of the transmission during various driving conditions.
2
Use an OBD-II scanner to check for any stored codes.
3
Check the transmission fluid level using the dipstick.
4
Check for software updates from Toyota.
5
Inspect the linkage between the gear shifter and the transmission.
6
Inspect the engine and transmission mounts for signs of wear or damage.

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

•OBD-II scanner
•Transmission dipstick
•Funnel
•Clean cloth
•Wrench set
•Jack
•Jack stands
•Visual inspection tools
•Drain pan

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Diagnostic Steps

1
Observe the behavior of the transmission during various driving conditions.
2
Use an OBD-II scanner to check for any stored codes.
3
Check the transmission fluid level using the dipstick.
4
Check for software updates from Toyota.
5
Inspect the linkage between the gear shifter and the transmission.
6
Inspect the engine and transmission mounts for signs of wear or damage.

Solution

Troubleshooting Rough Transmission Shifts in a 2020 Toyota Highlander

Repair Instructions

1. Change Transmission Fluid and Filter

If the fluid is dirty or low, changing it may resolve the issue.

Tools Required: Transmission fluid, new filter (if applicable), wrench set, funnel, drain pan.
Steps:
1. Lift the vehicle and secure it on jack stands.
2. Place a drain pan under the transmission pan.
3. Remove the transmission pan bolts and carefully drop the pan, allowing the fluid to drain.
4. Replace the transmission filter (if equipped) and clean the pan.
5. Reinstall the pan with a new gasket.
6. Using a funnel, refill the transmission with the appropriate fluid.

2. Update TCM Software

If the TCM has a software issue, updating it can resolve the shifting problem.

Tools Required: OBD-II scanner capable of reprogramming.
Steps:
1. Connect the scanner to the OBD-II port.
2. Download the latest software update from Toyota’s service portal.
3. Follow the on-screen instructions to upload the new software to the TCM.

3. Repair or Replace Transmission Linkage

If there are issues with the transmission linkage, it may need adjustment or replacement.

Tools Required: Wrench set, possibly new linkage parts.
Steps:
1. Adjust the linkage according to the service manual specifications.
2. If parts are damaged, remove the old linkage and replace it with new components.

4. Replace Engine/Transmission Mounts

If the mounts are worn, they will need to be replaced.

Tools Required: Jack, jack stands, socket set.
Steps:
1. Lift and secure the vehicle.
2. Support the engine and transmission with a jack.
3. Remove the old mounts and install new ones following the manufacturer’s specifications.

Final Steps

Test Drive: After performing the necessary repairs, take the vehicle for a test drive under various conditions to ensure the rough shifting has been resolved.
Re-check Fluid Levels: After the test drive, check the transmission fluid level and top off if necessary.
Address Any New Codes: If any new codes appeared during the test drive, address those before concluding the diagnosis.

Conclusion

If the rough transmission shift persists after all checks and repairs, it is advisable to consult a professional technician or a dealership for further diagnostics, as there may be internal transmission issues that require specialized tools and expertise.