2012 Toyota Highlander Transmission Problems
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8 Major 2012 Toyota Highlander Transmission Problems and Troubleshoot

Are you experiencing transmission problems in your 2012 Toyota Highlander? You’re not alone. Some owners have reported issues like rough shifting, delayed gear engagement, and complete transmission failure. 

These problems can lead to a compromised driving experience and safety concerns. If you’re facing such issues, having your vehicle inspected by a qualified mechanic is crucial to promptly diagnose and address transmission problems. 

Are common users experiencing 2012 Toyota Highlander Transmission Problems?

Some users have reported issues like rough shifting, delayed gear engagement, and complete transmission failure in the 2012 Toyota Highlander. Prompt inspection by a mechanic is crucial for diagnosis and resolution.

Let’s dive deeper into these issues and their causes. Also, explore their causes and the proactive steps taken to address them will be discussed in detail to give you some practical ideas.

A Brief Overview of the 2012 Toyota Highlander Transmission Problems, Causes and Solutions

The table below provides a glimpse of the 2012 Toyota Highlander transmission problems, Causes, and effective solutions.

1Transmission SlippingWorn clutch or bandsReplace worn clutch or bands
Low transmission fluid levelCheck and refill transmission fluid
2Transmission Fluid Burning SmellOverheating transmission fluidCheck cooling system and fluid levels
Dirty or contaminated fluidDrain and replace transmission fluid
3Transmission Fluid LeaksLoose or damaged sealsReplace or repair damaged seals
Cracked transmission housingRepair or replace housing as needed
4Transmission GrindingMisaligned or damaged gearsRepair or replace damaged gears
Contaminated transmission fluidFlush and replace transmission fluid
5Transmission Warning LightsFaulty sensors or solenoidsDiagnose and replace faulty components
Electrical issuesCheck and repair wiring as necessary
6Transmission Slipping When Driving UphillInsufficient transmission fluidCheck and refill transmission fluid
Worn or damaged clutchReplace worn or damaged clutch parts
7Transmission Not Properly MaintainedInfrequent fluid changesFollow the recommended maintenance schedule
Ignoring signs of transmission issuesAddress problems promptly
8Transmission Shifting DelaysFaulty shift solenoidsReplace malfunctioning solenoids
Low transmission fluid levelCheck and top up the transmission fluid

1. Transmission Slipping in 2012 Toyota Highlander

There are multiple reasons for transmission slipping in any vehicle. Let’s give you an overview of the usual culprits behind the transmission slipping of the Toyota Highlanders.

Worn Clutches

Over time, clutches in an automatic transmission can wear out due to factors like oil leaks in the clutch master cylinder or driver error. This can result in compromised clutch engagement and slipping during gear shifts, leading to delayed acceleration and decreased performance.

Solution − Replace the Worn Clutches

Step 1: Elevate the vehicle to access the transmission components. 

Step 2: Remove the transmission pan to gain entry to the transmission. 

Step 3: Inspect the clutches for signs of deterioration and damage. 

Step 4: Replace worn-out clutches with new ones to restore proper friction. 

Step 5: Reassemble the transmission components and lower the vehicle. 

Low Transmission Fluid

Inadequate fluid levels hinder proper lubrication and cooling within the transmission. Insufficient fluid can prevent the transmission from building the necessary hydraulic pressure to engage gears effectively. 

This can cause the transmission to overheat, leading to slipping and poor shifting performance.

Solution − Use Better Fluids

Step 1: Add the recommended transmission fluid if the fluid level is low. 

Step 2: Perform a driving test to identify any instances of slipping. 

Step 3: You can effectively resolve transmission slipping issues by addressing worn clutches and maintaining the correct fluid level.

2. Transmission Fluid Burning Smell in 2012 Toyota Highlander 

Find out the causes and solutions to the transmission fluid burning smell of your Toyota Highlander in the following section.

Transmission Fluid Burning Smell in 2012 Toyota Highlander 


Transmission fluid plays a crucial role in lubricating and cooling the transmission components. Overheating the transmission fluid due to excessive load, towing, or prolonged stop-and-go traffic can result in a burning smell. 

The fluid loses its ability to lubricate effectively, increasing friction and heat buildup.

Solution – Cool Down Your Heating Components

Step 1: Allow the vehicle’s transmission system to cool before inspection or maintenance. 

Step 2: Check for any clogs or obstructions in the transmission of more excellent lines that might impede proper fluid cooling. 

Step 3: Inspect the radiator and ensure it functions correctly to dissipate heat from the transmission fluid. 

Step 4: Address any underlying causes of overheating, such as a malfunctioning thermostat or radiator fan. 

Insufficient Fluid Levels

Low transmission fluid levels can lead to inadequate lubrication and poor cooling. This can cause the transmission components to generate more heat than the fluid can dissipate, resulting in the fluid breaking down and emitting a burnt smell.

How to Troubleshoot Insufficient Fluid Levels Problems

Step 1: If the fluid level is low, add the appropriate type of transmission fluid as recommended in the owner’s manual. 

Step 2: Regularly check and maintain the proper transmission fluid level to prevent future overheating.

3. Transmission Fluid Leaks in 2012 Toyota Highlander 

Your car runs on the fluid, and seals around that keep it running smoothly. Sometimes, the car might accidentally lose some of this fluid, which is called a transmission fluid leak. It’s important to fix this because if too much fluid leaks out, the car might not work properly.

Transmission Fluid Leaks in 2012 Toyota Highlander

Transmission Pan or Drain Plug

If the transmission pan gets punctured or the drain plug becomes loose, it can result in fluid leakage. A small puncture in the pan or improperly secured drain plugs can lead to fluid escaping from the transmission, causing leaks.

How to Troubleshoot Transmission Pan or Drain Plug Leaks

Step 1: Elevate the vehicle securely to access the transmission components. 

Step 2: Examine the transmission pan and drain plug for signs of damage or looseness. 

Step 3: If the drain plug is loose, tighten it to the recommended torque. If the pan is damaged, consider replacing it. 

Step 4: After addressing the issue, refill the transmission with the appropriate fluid. 

Broken Seals

Seals within the transmission, such as those around the input and output shafts, can become worn, warped, or damaged over time. These seals are exposed to high temperatures and can deteriorate, leading to fluid leaks from the transmission.

Solution for Broken Seal Leaks 

Step 1: Lift the vehicle to access the affected area. 

Step 2: Inspect the seals around the transmission system, focusing on axle seals and input shaft seals. 

Step 3: If a seal is damaged or broken, carefully remove it and replace it with a new one. 

Step 4: Reassemble the components and refill the transmission fluid as needed.

4. Transmission Warning Lights in 2012 Toyota Highlander 

Reasons for transmission warning light failure can stem from low fluid, overheating, shift interlock problems, internal failures, or valve body malfunctions, requiring timely inspection and repair. Let’s get you educated behind the scenes.

Electrical Malfunctions

Transmission warning lights can illuminate due to electrical issues within the transmission system. These issues could stem from malfunctions in sensors, solenoids, or other electrical components responsible for the proper functioning of the transmission. 

A simple electrical malfunction can send incorrect signals to the vehicle’s computer, triggering the warning light.

How to Troubleshoot the Electrical Malfunctions

Step 1: Check for loose or damaged electrical connections related to the transmission. 

Step 2: If there are no visible issues, use a diagnostic tool to scan for error codes. 

Step 3: Address the specific electrical problem based on the error code and repair or replace components. 

Transmission Fluid Issues

Low transmission fluid levels or problems with the transmission fluid can trigger the warning light. Low fluid levels can result in inadequate lubrication and cooling, potentially damaging transmission. 

Similarly, issues like overheating or contaminated fluid can also cause the warning light to illuminate.

How to Troubleshoot the Transmission Fluid Issues 

Step 1: Locate the transmission dipstick and check the fluid level and condition. 

Step 2: If the fluid level is low, introduce the recommended transmission fluid to the appropriate level. 

Step 3: If the fluid is degraded, perform a transmission fluid flush and replace it with fresh fluid.

5. Transmission Grinding in 2012 Toyota Highlander 

Reasons for transmission grinding encompass low fluid levels, clutch misadjustment, poor driving habits, inadequate maintenance, and potential synchronizer or bearing issues. Professional evaluation may reveal other complex causes.

Worn Clutch Components

A grinding noise during shifting can result from worn clutch components, especially in manual transmissions. The clutch disc, pressure plate, or flywheel may be worn, leading to improper engagement and the grinding sensation when gears are shifted.

How to Troubleshoot Worn Clutch Components 

Step 1: Diagnose the extent of clutch wear through inspection. 

Step 2: Replace worn clutch components, including the disc and pressure plate. 

Step 3: Ensure proper adjustment of the clutch pedal and linkage. 

Step 4: Test drive to verify that the grinding noise has been eliminated.

Synchronizer Issues

Synchronizers help match the speeds of gears for smoother shifting. If synchronizers are damaged or worn, gears may not engage seamlessly, causing grinding noises. Damaged blocking rings, shift forks, or bearings can lead to synchronizer issues.

How to Troubleshoot Synchronizer Issues 

Step 1: Drain and replace the transmission fluid with the manufacturer-recommended fluid. 

Step 2: Inspect and replace damaged or worn synchronizers. 

Step 3: Verify proper adjustment of the shift linkage. 

Step 4: Test the vehicle to ensure smooth gear shifting without grinding.

6. Transmission Slipping When Driving Uphill 

Transmission slipping when driving uphill is often due to low fluid levels and worn gear bands. Maintenance, gear selection, and addressing related issues can prevent this frustrating problem. Here are the main culprits behind this.

Low Transmission Fluid

Insufficient transmission fluid can lead to inadequate hydraulic pressure to engage gears effectively, causing slipping. Uphill driving increases the demand on the transmission, making low fluid levels more pronounced in causing slipping.

How to Troubleshoot Low Transmission Fluid 

Step 1: Park the vehicle on a level surface and engage the parking brake. 

Step 2: If the fluid level is low, gradually add the recommended transmission fluid type. 

Step 3: Test drive to ensure proper uphill performance. 

Worn Clutch or Bands

Worn clutch plates or transmission bands may struggle to maintain proper grip on the gears, particularly under increased load while driving uphill. This can lead to slippage between gears and result in noticeable slipping sensations.

How to Troubleshoot Worn Clutch or Bands 

Step 1: Consult a professional mechanic for a thorough transmission inspection. 

Step 2: If clutch plates or bands are worn, replace them with new components. 

Step 3: Ensure the proper adjustment of clutch linkage or bands. 

Step 4: Test drive to confirm that the uphill slipping issue has been resolved.

7. Transmission Not Properly Maintained

Sometimes, it’s the owner’s lack of care that makes these beautiful and sustainable Toyota machines go south. Take a look.

Lack of Regular Maintenance

Adherence to recommended maintenance schedules can lead to various transmission issues, including degraded fluid quality, clogged filters, and worn components. Over time, this lack of maintenance can cause the transmission to malfunction or fail.

How to Troubleshoot Lack of Regular Maintenance 

Step 1: Consult the vehicle’s owner manual for recommended maintenance schedules. 

Step 2: Regularly change the transmission fluid and replace the filter according to the manufacturer’s guidelines. 

Step 3: Inspect the transmission system for wear signs and promptly address any issues. 

Dirty or Contaminated Fluid

Neglecting transmission fluid changes can result in dirty, contaminated fluid that loses its ability to lubricate and cool the transmission components properly. Contaminated fluid can lead to increased friction, overheating, and accelerated wear.

How to Troubleshoot Dirty or Contaminated Fluid 

Step 1: Perform a transmission flush to remove old, contaminated fluid. 

Step 2: Replace the fluid with the manufacturer-recommended type. 

Step 3: Monitor the fluid level and quality regularly and address any leaks promptly.

8. Transmission Shifting Delays 

Transmission shifting delays can arise from issues like a bad torque converter, overheating, clogged filter, dirty oil, valve body problems, solenoid defects, burnt clutch disc, or worn gears, demanding prompt attention. 

Worn Clutch Components

A worn clutch can lead to delayed engagement and disengagement of gears, resulting in shifting delays. Factors like oil leaks in the clutch master cylinder or driver error can cause clutch wear.

How to Troubleshoot Worn Clutch Components 

Step 1: Consult a professional mechanic to inspect the clutch system thoroughly. 

Step 2: Replace worn-out clutch components, including the clutch plate, pressure plate, and release bearing. 

Step 3: Ensure proper clutch adjustment to enable smooth gear engagement. 

Transmission Fluid Issues

Poor conditions or lack of transmission fluid can cause slipping, rough shifting, and delayed engagement. Incorrect fluid type or insufficient fluid levels can impact how gears engage and disengage, leading to delays.

How to Troubleshoot Transmission Fluid Issues 

Step 1: Check the transmission fluid level and quality. If low or degraded, perform a fluid change according to the manufacturer’s recommendations. 

Step 2: Use the correct type of transmission fluid specified for the vehicle. 

Step 3: Regularly monitor the transmission fluid and address any leaks promptly.

Watch this video:

Other Common 2012 Toyota Highlander Problems

The 2012 Highlander, for instance, has had its fair share of reported problems. While many owners rave about its performance and reliability, others have pointed out specific concerns that potential buyers and current owners should be aware of. If you’re considering a used Highlander or want to ensure your current ride stays in top shape, it’s essential to familiarize yourself with these issues. Dive deeper into our comprehensive article that outlines the 2012 Toyota Highlander problems to get a clearer picture.

Final Words

It’s essential to comprehend and care for any prospective 2012 Toyota Highlander Transmission Problems when navigating the world of automobile complexities. 

Even though not all vehicles may have these problems, being aware of fluid leaks, slipping gears, and other issues gives owners the power to take preventative action. 

In the long run, routine maintenance, prompt repairs, and attention to warning indications can all lead to a more dependable and pleasurable driving experience, preserving the reputation of the 2012 Toyota Highlander.

Frequently Asked Questions

1. What are some indications of transmission difficulties in the 2012 Toyota Highlander? 

Be cautious of irregular gear shifts, gears slipping where the engine revs without accelerating, fluid leakage, and uncommon sounds such as whining or clunking. 

2. Why does the transmission fluid in my 2012 Highlander emit a burnt smell? 

A burnt usually implies that the transmission is overheating, leading to fluid deterioration, or it could be contaminated due to internal complications. It is advisable to seek professional inspection.

3. How can I avert transmission problems in my 2012 Highlander?

Consistently maintain your transmission by inspecting and replacing the fluid, promptly addressing leaks, and adopting smooth driving habits. This can aid in prolonging its lifespan.

4. What should I do if I observe the transmission warning light illuminated in my Highlander? 

If the transmission warning light is activated, it signifies a potential issue. Consult a skilled mechanic to diagnose the problem and carry out necessary repairs to prevent further damage.


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  2. https://absolutetransmissionrebuild.com/fluid-smells-burnt/
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  5. https://www.vehiclehistory.com/report/toyota/highlander/2012
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  7. https://gomechanic.in/blog/problems-with-an-automatic-transmission/
  8. https://oorpogl.logopromotie.nl/difficult-maths-questions-for-class-5.html

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