2020 Toyota Highlander

After my 75000 mile inspection at my Toyota dealership, which is required and I have been bring my vehicle in every 5,000 miles. I started hearing a slight whinny noise. I thought it was around my wheels or tires. Then I thought it must be a new wind noise. Which that is another issue. I took a short trip and by the time I got back it was louder. I took it to the dealership and the technician drove it and said I need a new transmission. I ask my service provider if he has seen any other vehicles having this problem? And I should not have any transmission issues at this mileage. My service provider stated that he knows of highlanders having this issues.

At around 45,000 miles, my 2020 Toyota Highlander started making a whining noise on acceleration. This condition seemed to get worse (whining got louder) I took it to a Toyota dealership and they said there are no codes left by the vehicle but the repair technician knows that this whine is related to a total transmission failure so the recommendation is to replace the transmission at a cost of approximately $8000, Toyota said the vehicle is out of warranty (by 4 months) so they will offer nothing to assist with the repair. Looking on the internet and this website, it is very clear that this is a common issue with this model of vehicle. Dealer said I can drive it but eventually the transmission will fail, leaving me stranded on the roadside.

I am filing a complaint with the NHTSA regarding persistent transmission slipping in my 2020 Toyota Highlander LE equipped with the UA80-E 8-speed automatic transmission. Since reaching approximately 55,000 miles, I have experienced noticeable slipping, characterized by delayed acceleration, erratic shifting, and occasional lurching, which align with documented defects in the UA80 platform as outlined in over 430 NHTSA complaints and Toyota’s Technical Service Bulletins (e.g., T-SB-0160-18 and T-SB-0008-21). These issues stem from a known manufacturing flaw involving a washer tab failing to secure the counter drive gear’s retaining nut, leading to gear movement, internal wear, and symptoms like mine. This defect, prompting Toyota’s Customer Support Program ZJC for 2017–2018 models and reported in later years like 2020, compromises vehicle safety and reliability, as slipping can cause unpredictable handling. I urge the NHTSA to investigate further and hold Toyota accountable for addressing this widespread issue across affected models.

On September 2, 2025, the vehicle’s Hybrid System shut down on cold start and the vehicle would not start. A dealer inspection reported coolant had entered cylinder #4, allegedly causing the engine block to warp, the cylinder head to crack, and the head gasket to fail. This was a sudden catastrophic engine failure on a five-year-old vehicle with no prior overheating warnings, no dashboard alerts, and no performance issues in the days leading up to the failure. It is highly unlikely for an engine block to warp without sustained overheating, yet the failure occurred on a cold start. The dealership itself described this as a “premature failure” in their service report. At approximately 26,000 miles, the vehicle’s coolant thermostat failed and was replaced under warranty. If the thermostat stuck closed even briefly, the engine could have experienced one or more silent overheat events that never registered on the dashboard. In aluminum blocks, even short bursts of high localized heat can create latent distortion that doesn’t cause immediate problems but can eventually lead to catastrophic failure years later. Safety Risk: – Vehicle became disabled suddenly without warning. – Engine failure occurred without overheating symptoms, creating risk of sudden shutdown during use. Problem Confirmation: – Engine failure confirmed by a Toyota-authorized dealer. – Dealer service report explicitly called this a “premature failure.” Warning Lamps / Symptoms: – A check engine light appeared briefly three days before failure, then cleared on its own. – No overheating warnings or drivability issues were observed prior to failure.

The contact owns a 2020 Toyota Highlander. The contact stated that while driving at 30 MPH, there was an abnormal whining sound coming from underneath the vehicle. No warning lights were illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the transmission. The vehicle was not repaired. The manufacturer was notified of the failure, and a case was opened. The failure mileage was 78,000.

All of the sudden around 70K miles, the transmission started to make a "whining" noise. It does not sound right and I'm afraid the transmission could fail while I'm driving. I took it to the dealer and they acknowledged that it's a known issue but that in my case the noise is not loud enough to warrant replacing the transmission. A quick research on the internet revels that this is a very common problem.

My 2020 vehicle has 75,000 miles on it. It started making a high pitched sound when accelerating. I brought my vehicle to the dealership where I bought it, to have it inspected. I was assuming it would be a belt or an easy fix. The service agent walked over and cooly explained that I need a new transmission. He continued to say that this is a common issue with this make and model. He stated that at the beginning of the year customers were having to wait a couple of months of transmission parts, but now because of the demand due to the well known power train failure, that the current wait time for transmission parts are only two weeks. He stated several times, that this is a common problem, one that car owners are expected to pay $9,000. to fix. A quick google search brings up a plethora of customers having the same exact problem. Toyota needs to make this right and issue a recall on their faulty product.