2020 Toyota Highlander: hesitation when accelerating

Filed Oct 2, 2026 · Transmission · MS

• What component or system failed or malfunctioned, and is it available for inspection upon request? The UA80 8-speed automatic transmission assembly (specifically internal mechanical wear resulting from front carrier assembly bearing degradation/torque converter heat buildup). No, the component and the contaminated transmission fluid are currently being replaced at the dealership. • How was your safety or the safety of others put at risk? The severe mechanical wear and metal-on-metal degradation inside the transmission create an imminent hazard where the vehicle can experience sudden slipping, severe hesitation, or a complete, unexpected loss of motive power while traveling at highway speeds. This loss of acceleration in active traffic creates an immediate risk of a rear-end collision and leaves passengers stranded in an unsafe traffic pattern without warning. • Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. A professional diagnostic inspection confirmed that the transmission fluid was catastrophically low, and the assembly sustained severe internal damage via metal-on-metal contact with metal shavings actively circulating throughout the unit. • Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? The vehicle has been inspected and diagnosed by a service facility. It has not been inspected by the police or insurance representatives, as no crash has occurred yet. However, this failure directly mirrors the mechanical defects acknowledged by the manufacturer in Toyota Technical Service Bulletin T-SB-0008-21 and active federal class-action lawsuits. • Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? There were no electronic dashboard warning lamps or no electronic dashboard warning lamps or visible signs of prior leakage/seepage.

Filed Apr 2, 2026 · Acceleration · VA

The vehicle is a 2020 Toyota Highlander experiencing a transmission system malfunction, specifically involving the automatic transmission and/or torque converter. Component/System Failure: The transmission produces a noticeable whining noise during acceleration and exhibits abnormal shifting behavior, including hesitation and delayed response when pressing the gas pedal. The issue appears to originate from the internal transmission components. The vehicle is available for inspection upon request. Safety Risk: This condition creates a serious safety concern, as the hesitation and delayed acceleration can impair the driver’s ability to safely merge into traffic, cross intersections, or respond to changing road conditions. The unpredictable response increases the risk of a collision, especially in high-speed or congested traffic environments. Reproducibility / Confirmation: The issue is consistently reproducible and occurs whenever the vehicle is accelerated. The problem has not yet been fully resolved and is in the process of being addressed with a dealership/service center. Inspections: The vehicle is scheduled to be inspected by a Toyota dealership. At this time, it has not yet been inspected by the manufacturer, police, or insurance representatives. Warning Signs / Symptoms: There were no warning lights or dashboard messages prior to or during the issue. The first symptom noticed was the whining noise during acceleration, followed by abnormal shifting behavior and hesitation. These symptoms have progressively become more noticeable over time. This issue appears consistent with reported transmission problems in similar model vehicles, raising concern that this may be a broader defect affecting vehicle safety. I took my vehicle to 3 different mechanics and they told me that my vehicle is not safe to drive long term without a total transmission replacement. Thank you!

Filed Mar 16, 2026 · Transmission · NY

My 2020 Toyota Highlander experiences transmission jerking and hesitation during low speed acceleration. The issue was first reported to the dealership while under warranty but was not diagnosed. The vehicle now requires transmission replacement 7k miles over the warranty despite the issue being reported during the warranty. Toyota has refused a repair under warranty and has violated their terms of powertrain warranty. This 8 speed transmission commonly has issue during production years 2017-2022 and toyota has admitted to a production defect. Despite that they have refused a goodwill repair or a warranty repair.

Filed Feb 20, 2026 · Acceleration, Transmission · ME

At approximately 120,000 miles, the vehicle began exhibiting a pronounced shudder or vibration between 40–50 mph under light acceleration or steady cruising. The condition progressed to delayed shifting and intermittent loss of acceleration response. The most concerning issue is hesitation and reduced acceleration when attempting to merge into traffic or increase speed. On multiple occasions, the vehicle failed to respond promptly to throttle input, creating a potential safety hazard due to loss of propulsion. The vehicle was evaluated at two authorized Toyota dealerships. Both indicated that the condition is consistent with torque converter or transmission failure. Full transmission replacement was recommended at an estimated cost of approximately $9,000. No whining or grinding noises are present; symptoms primarily involve shuddering and hesitation. The vehicle has not been driven since October 21, 2025, due to safety concerns and to prevent further damage. The vehicle has been regularly maintained at Toyota dealerships and has not been used for towing. This complaint concerns loss of acceleration, transmission shudder, and potential premature failure of the 8-speed automatic transmission.

Filed Dec 4, 2025 · Transmission · UT

The vehicle’s automatic transmission (power train) has developed a loud whining/whirring noise under acceleration. This noise increases with engine load and indicates internal mechanical failure. The transmission is still installed in the vehicle and is available for inspection upon request. This issue poses a safety risk because it causes hesitation and unpredictable acceleration behavior while merging or crossing traffic. There is also concern that the transmission could suddenly fail while driving, resulting in loss of propulsion and potentially causing an accident. The problem has been inspected and confirmed by a Toyota dealership, which advised that the entire transmission needs to be replaced at a cost of over $8,000, despite the vehicle having only approximately 77,000 miles. The vehicle has been inspected by a Toyota manufacturer service center. They identified the transmission failure but stated there are no current recall programs covering this specific VIN. No warning lights or error messages were displayed at any time before or during the failure. The first noticeable symptom was the transmission whining/whirring noise during acceleration, which began around 77,000 miles and continues to worsen.

Filed Sep 10, 2025 · Transmission · GA

Transmission whine Owners of 2017–2022 Toyota Highlanders, 2017–2020 Siennas, and 2018–2020 Camrys are experiencing serious transmission issues—including high-pitched whining, erratic shifting, clunks, hesitation, and premature failure. These vehicles are equipped with the UA80F (AWD) and UA80E (FWD) 8-speed automatic transmissions.

Filed May 14, 2024 · Transmission · TX

Transmission began whining and hesitating around 62K miles. Transmission is the 8AT.

Filed May 26, 2020 · Electrical · 50 miles · FL

The vehicle hesitates, stalls and has bucking leaping forward uncontrollably, on the road. The vehicle also has a very loud whining noise upon shifting the car from park to drive and back again from drive to park, at a stand still. This is a major issue with a nee car, my wife and I don't feel safe while driving in this car.