why is my Toyota Highlander Third Generation (2014-2019) transmission slipping

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

4 min read

617 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 fix transmission slipping in Toyota Highlander (2014-2019). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

Affected Component

Transmission

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Allow the engine to cool before opening the transmission pan to avoid burns.

Symptoms

•Engine RPM increases without corresponding vehicle acceleration
•Delayed or harsh shifting between gears
•Transmission warning light illuminated on the dashboard
•Fluid leaks under the vehicle
•Burning smell from the transmission area
•Unusual noises (grinding or whining) during operation

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify potential transmission issues.
2
Check the transmission fluid level and condition, looking for discoloration or a burnt smell.
3
Inspect the transmission fluid for leaks around seals and gaskets.
4
Test the transmission solenoids with a multimeter for proper resistance.
5
Examine the condition of the transmission filter.
6
Inspect the transmission control module (TCM) for any faults or malfunction indicators.

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
•Socket set
•Multimeter
•Funnel

Parts Required

•Transmission fluid (Toyota WS)
•Transmission filter
•Gasket for transmission pan
•Solenoids (if necessary)
•TCM (if necessary)

Related Faults

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify potential transmission issues.
2
Check the transmission fluid level and condition, looking for discoloration or a burnt smell.
3
Inspect the transmission fluid for leaks around seals and gaskets.
4
Test the transmission solenoids with a multimeter for proper resistance.
5
Examine the condition of the transmission filter.
6
Inspect the transmission control module (TCM) for any faults or malfunction indicators.

Solution

1. Preparation

Gather necessary tools and materials.
Park the vehicle on a level surface and engage the parking brake.
Disconnect the battery to ensure safety while working on electrical components.

2. Check and Replace Transmission Fluid

Tools Required: Socket set, funnel, transmission fluid.
Remove the transmission fluid dipstick and check the fluid level.
If low, add the appropriate type of Toyota transmission fluid (WS).
If burnt or contaminated, proceed to drain and replace the fluid.
- Locate the transmission fluid pan, remove the bolts, and drain the old fluid into a suitable container.
- Replace the pan gasket if necessary, and reattach the pan with bolts tightened to manufacturer specifications (typically around 8-10 ft-lbs).
- Refill with new transmission fluid using a funnel.

3. Inspect and Replace Transmission Filter

Tools Required: Socket set, new transmission filter, gasket.
Remove the transmission pan as described above.
Take out the old filter and discard it.
Install the new filter, ensuring it is seated correctly.
Replace the pan (with a new gasket if necessary) and tighten the bolts to the specified torque.

4. Test Transmission Solenoids

Tools Required: Multimeter.
Disconnect the electrical connectors from the solenoids.
Use the multimeter to check the resistance of each solenoid, comparing with manufacturer specifications (usually between 20-30 ohms).
If any solenoid is out of range, replace it with a new one.

5. Inspect and Replace Transmission Control Module (if necessary)

Tools Required: Diagnostic scanner, basic hand tools.
If error codes indicate a TCM issue, locate it (usually under the dashboard or in the engine compartment).
Disconnect the battery, then remove the TCM and inspect for damage or corrosion.
Replace with a new TCM if necessary, and reprogram it if the model requires.