Let’s face it, you bought a Toyota Highlander for its reliability, its spaciousness, and its reputation for lasting forever. So, discovering potential transmission problems in your 2021 model can be a real gut punch. While the 2021 Highlander is generally a dependable vehicle, some owners have reported issues with its 8-speed automatic transmission. We're here to break down what these problems are, what might be causing them, and what you can do about it.

So, What's the Buzz About the 2021 Highlander's Transmission?

The 2021 Toyota Highlander uses an 8-speed automatic transmission, designed to improve fuel economy and provide smooth shifting. Unfortunately, some owners have experienced a variety of issues, including:

  • Harsh Shifting: This is one of the most common complaints. Owners report experiencing jarring or clunky shifts, particularly between lower gears. It feels less like a seamless transition and more like a sudden jolt.

  • Hesitation or Delay in Shifting: Sometimes, the transmission might hesitate or delay before shifting gears, especially when accelerating from a stop or trying to pass another vehicle. This can be unsettling and even dangerous in certain driving situations.

  • Slipping Gears: Gear slippage occurs when the transmission momentarily loses its grip on the gears, causing the engine to rev without a corresponding increase in speed. This can feel like the car is briefly losing power.

  • Shuddering or Vibrating: Some owners report experiencing a shuddering or vibrating sensation, particularly at lower speeds or during light acceleration. This can be a sign of internal transmission issues.

  • Unusual Noises: Whining, clunking, or other unusual noises coming from the transmission area can be a warning sign of a problem.

  • Transmission Failure: In more severe cases, some owners have experienced complete transmission failure, requiring costly repairs or replacements.

Okay, But How Widespread Are These Issues Really?

It's important to put these reports into perspective. While some owners have experienced transmission problems with their 2021 Highlanders, it's not necessarily a widespread epidemic. Toyota sells a lot of Highlanders, and even a small percentage of issues can translate to a significant number of complaints online. That being said, any transmission problem is a concern, especially in a vehicle known for its reliability.

One of the best places to gauge the extent of these issues is to check online forums and complaint databases like the National Highway Traffic Safety Administration (NHTSA). You can search for specific complaints related to the 2021 Highlander's transmission to see if others are experiencing similar problems. This can give you a better sense of how common these issues might be.

What Could Be Causing These Transmission Troubles?

Pinpointing the exact cause of these transmission problems can be tricky, as there are several potential culprits. Here are some of the most common possibilities:

  • Software Glitches: Modern transmissions are controlled by sophisticated software. Glitches or bugs in this software can sometimes cause erratic shifting behavior. A software update from Toyota might be able to resolve these issues.

  • Valve Body Issues: The valve body is a critical component of the transmission that controls the flow of hydraulic fluid. Malfunctions in the valve body can lead to shifting problems, hesitation, or gear slippage.

  • Torque Converter Problems: The torque converter is responsible for transferring power from the engine to the transmission. Issues with the torque converter can cause shuddering, vibrations, or a complete loss of power.

  • Internal Component Wear: Over time, the internal components of the transmission, such as gears, clutches, and bearings, can wear down. This wear can lead to shifting problems, noises, or even transmission failure.

  • Low Transmission Fluid: Insufficient transmission fluid can cause a variety of problems, including harsh shifting, slipping gears, and overheating. Regular maintenance, including checking and topping off the transmission fluid, is crucial. Always use the correct type of transmission fluid specified by Toyota.

  • Manufacturing Defects: In rare cases, transmission problems can be traced back to manufacturing defects in the transmission itself.

What Should You Do If You Suspect a Transmission Problem?

If you're experiencing any of the symptoms described above, it's important to take action promptly. Ignoring the problem could lead to more serious damage and costly repairs down the road. Here's what you should do:

  1. Document the Problem: Keep a detailed record of when the problem occurs, what it feels like, and any other relevant information. This will be helpful for the mechanic when diagnosing the issue.

  2. Check the Transmission Fluid: Inspect the transmission fluid level and condition. Low or dirty fluid can often contribute to shifting problems. Refer to your owner's manual for instructions on how to check the fluid. Never overfill the transmission fluid.

  3. Schedule a Diagnostic Check: Take your Highlander to a qualified mechanic who specializes in transmissions. They can perform a thorough diagnostic check to identify the root cause of the problem.

  4. Inquire About Software Updates: Ask the mechanic if there are any available software updates for the transmission control module. A software update might be able to resolve some shifting issues.

  5. Get a Second Opinion: If you're not comfortable with the mechanic's diagnosis or recommended repairs, it's always a good idea to get a second opinion from another qualified mechanic.

  6. Contact Toyota: If you believe the transmission problem is covered under warranty, contact your local Toyota dealership or Toyota's customer service department. They can advise you on the warranty coverage and repair options.

Is Your Transmission Covered Under Warranty?

The 2021 Toyota Highlander typically comes with a basic warranty that covers defects in materials or workmanship for a certain period of time or mileage. The powertrain warranty, which covers the engine and transmission, usually extends for a longer period. Check your warranty paperwork to determine the specific coverage for your vehicle.

If your Highlander is still under warranty, the transmission repairs may be covered by Toyota. However, it's important to note that the warranty may not cover damage caused by neglect, abuse, or improper maintenance.

Preventive Maintenance: Keeping Your Transmission Happy

Even if you're not currently experiencing any transmission problems, it's important to take steps to prevent them from occurring in the future. Here are some preventive maintenance tips:

  • Follow the Recommended Maintenance Schedule: Adhere to the maintenance schedule outlined in your owner's manual. This includes regular transmission fluid changes.

  • Use the Correct Transmission Fluid: Always use the type of transmission fluid specified by Toyota. Using the wrong fluid can damage the transmission.

  • Avoid Hard Acceleration and Braking: Aggressive driving habits can put extra stress on the transmission.

  • Don't Tow Beyond the Recommended Limit: Towing beyond the Highlander's recommended towing capacity can overload the transmission.

  • Get Regular Transmission Inspections: Have your transmission inspected by a qualified mechanic during regular maintenance visits.

What About Recalls or Technical Service Bulletins (TSBs)?

It's always a good idea to check for any recalls or Technical Service Bulletins (TSBs) related to your 2021 Toyota Highlander's transmission.

  • Recalls: Recalls are issued by Toyota (or NHTSA) when there is a safety-related defect in the vehicle. The manufacturer is required to fix the defect free of charge.

  • Technical Service Bulletins (TSBs): TSBs are issued by Toyota to provide guidance to technicians on how to diagnose and repair common problems. TSBs are not recalls, but they can provide valuable information about potential issues.

You can check for recalls and TSBs on the NHTSA website or by contacting your local Toyota dealership.

Frequently Asked Questions

  • Why is my 2021 Highlander shifting so hard?
    Harsh shifting can be caused by software glitches, valve body issues, or low transmission fluid. Have a mechanic diagnose the problem.

  • Is it normal for my Highlander's transmission to hesitate?
    A slight hesitation can be normal, but excessive hesitation could indicate a problem. Schedule a diagnostic check to rule out any serious issues.

  • How often should I change my transmission fluid?
    Refer to your owner's manual for the recommended transmission fluid change interval. Typically, it's between 60,000 and 100,000 miles, but conditions can vary.

  • Can I check my transmission fluid myself?
    Yes, you can check the transmission fluid level using the dipstick. Refer to your owner's manual for instructions.

  • Will a software update fix my transmission problems?
    In some cases, a software update can resolve shifting issues. Ask your mechanic if there are any available updates.

Wrapping Things Up

While some 2021 Toyota Highlander owners have reported transmission problems, it's not necessarily a widespread issue. By understanding the potential problems, taking preventive measures, and seeking prompt diagnosis and repair, you can help keep your Highlander's transmission running smoothly for years to come. If you suspect an issue, document it and get it checked by a qualified professional.