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

Toyota Highlander Third Generation (2014-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

high

Severity

3 min read

556 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 issues in the 2014-2019 Toyota Highlander. Step-by-step guide with diagnostic procedures 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

•Transmission slips when accelerating
•Engine revs without an increase in vehicle speed
•Delayed engagement when shifting from park to drive
•Unusual noises (grinding or whining) during acceleration
•Check engine light may be illuminated

Diagnostic Steps

1
Check the transmission fluid level and condition using the dipstick.
2
Inspect for any transmission fluid leaks underneath the vehicle.
3
Scan the vehicle's onboard computer for any error codes related to the transmission.
4
Perform a visual inspection of the transmission wiring harness and connectors for damage or corrosion.
5
Test drive the vehicle to replicate the slipping condition and observe any unusual behaviors.
6
Check the condition of the transmission filter and screen.

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 fluid pump
•Socket set
•Multimeter
•Screwdrivers
•Funnel

Parts Required

•Toyota ATF WS transmission fluid
•Transmission filter
•Transmission pan gasket

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Check the transmission fluid level and condition using the dipstick.
2
Inspect for any transmission fluid leaks underneath the vehicle.
3
Scan the vehicle's onboard computer for any error codes related to the transmission.
4
Perform a visual inspection of the transmission wiring harness and connectors for damage or corrosion.
5
Test drive the vehicle to replicate the slipping condition and observe any unusual behaviors.
6
Check the condition of the transmission filter and screen.

Solution

1. Preparation

Gather tools and parts required for the repair.
Ensure the vehicle is parked on a level surface and the engine is cool.
Disconnect the battery to prevent electrical shorts.

2. Check and Replace Transmission Fluid

Tools Required: Funnel, transmission fluid, fluid pump.
Sub-steps:
1. Remove the transmission dipstick and wipe it clean.
2. Insert the dipstick back and check the fluid level; add fluid if low.
3. If the fluid is burnt or contaminated, drain the transmission fluid using a fluid pump.
4. Replace with the manufacturer-recommended transmission fluid type (typically Toyota ATF WS).
5. Recheck the fluid level and ensure it is within the acceptable range.

3. Replace Transmission Filter

Tools Required: Socket set, screwdrivers, gasket scraper.
Sub-steps:
1. Remove the transmission pan using a socket set; be prepared for fluid spillage.
2. Remove the old filter and replace it with a new one.
3. Clean the gasket surface on the transmission case.
4. Install a new gasket and reattach the transmission pan, tightening to manufacturer torque specifications.

4. Inspect and Repair Wiring and Connectors

Tools Required: Multimeter, wire crimping tool.
Sub-steps:
1. Inspect the wiring harness connected to the transmission for any visible damage.
2. Use a multimeter to check for continuity and proper voltage.
3. Repair or replace any damaged wiring or connectors as necessary.

5. Reconnect Battery and Test

Reconnect the battery terminals.
Start the vehicle and allow it to warm up.
Test drive to ensure the slipping issue has been resolved.