TT: Some 2014-2021 model year vehicles equipped with Dynamic Torque Control AWD system may experience a ?Noise? or ?Abnormal Operation? condition from the rear differential front coupling. In some cases, even an ?AWD System Message? with or without a DTC may be present with or without other conditions present.
full bulletin at NHTSA ↗2020 Toyota Highlander powertrain problems
moderate Owners of the 2020 Toyota Highlander have filed 118 NHTSA complaints about the powertrain, typically surfacing around 78,000 miles at roughly $2,500 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Failure mileage
Complaints
118
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2017 Highlander | 69 |
| 2018 Highlander | 57 |
| 2019 Highlander | 181 |
| 2020 Highlander (this page) | 118 |
| 2021 Highlander | 192 |
| 2022 Highlander | 47 |
| 2023 Highlander | 15 |
| 2024 Highlander | 3 |
2crashes
1injury
When does it fail?
Of the 118 powertrain complaints filed for the 2020 Toyota Highlander, here's the actual mileage breakdown — failures cluster heaviest at 50,000-75,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Powertrain accounts for 39% of every owner complaint on file for this vehicle — the dominant problem area across 11 categories tracked.
Owners have filed 118 powertrain complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
TT: Currently under investigation. Please contact TAS if you have a vehicle that exhibits a leak from the Transmission Side Cover with no signs of damage or other conditions unrelated to regardless of miles or months in service. If it?s a Sunday or holiday continue with diagnosis and repair, save all parts and details, contact TAS on the next available work day and review details with TAS engineer.
full bulletin at NHTSA ↗TT: Some 2018-2020 model year UA80/UB80 transmission equipped models may experience a leak from the Transmission Side Cover. This issue is currently under investigation. Vehicles are being sought regardless of months in service or mileage. Only seeking vehicles with leaking transmissions with no other signs of damage to the side cover.
full bulletin at NHTSA ↗TSB: REVISION NOTICE July 01, 2019 Rev2: ? Applicability has been updated to 2019 ? 2020 model year Toyota vehicles. ? The Techstream Preparation and Process Overview sections have been updated. October 30, 2017 Rev1: ? Applicability has been updated to include 2018 model year vehicles. Any previous printed versions of this bulletin should be discarded. SUPERSESSION NOTICE The information contained in this bulletin supersedes SB No. T-SB-0012-13. Service Bulletin No. T-SB-0012-13 is obsolete and any printed versions should be discarded. Be sure to review the entire content of this bulletin before proceeding. Flash reprogramming allows the Electronic Control Unit (ECU) software to be updated
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The overwhelming majority of complaints center on the UA80 8-speed automatic transmission failing prematurely—typically between 55,000 and 80,000 miles. Owners first hear a loud whining or whirring noise during acceleration that increases with engine load and vehicle speed. The sound appears without warning, no dashboard lights illuminate, and it progressively worsens over days or weeks. Dealership diagnostics confirm internal bearing failure or counter drive gear wear; the prescribed fix is full transmission replacement at $8,000–$13,000.
The pattern is consistent: symptoms emerge near or just after the 60,000-mile/5-year powertrain warranty expires. Many owners report the whining began *within* warranty but weren't aware it signaled transmission failure, so they didn't seek service until later. Toyota acknowledges the defect in Technical Service Bulletin T-SB-0008-21 and ran a Customer Support Program (ZJC) for 2017–2018 models but has not extended coverage to 2020 Highlanders despite identical transmission design. Dealers rarely assist; parts routinely sit on backorder for 1–3 months, leaving owners unable to drive the vehicle.
Some owners also report transmission slipping—hesitation or delayed acceleration when pressing the throttle—that creates dangerous merging situations. Two isolated complaints describe the parked vehicle rolling away without engine running or warning. One complaint involves catastrophic engine failure from coolant intrusion after a thermostat replacement, though this is distinct from the transmission issue dominating the set. Throughout, owners emphasize Toyota's silence despite widespread online discussion of the problem.
Same Toyota Highlander powertrain reports on nearby years: 2017 · 2018 · 2019 · 2021 · 2022
Failure modes owners describe
Transmission whining/whirring noise under acceleration
Owners report a loud, high-pitched whining or whirring sound from the transmission that increases with engine load and appears during acceleration, particularly between 25–60 mph. The noise often stops when the accelerator is released. It indicates internal mechanical failure, typically bearing wear or gear damage. Owners consistently describe the symptom as starting without warning and progressing over time.
When: Typically between 45,000–110,000 miles; clusters heavily between 55,000–79,000 miles. Many failures occur near or just after the 60,000-mile/5-year powertrain warranty boundary.
Symptoms owners cite: High-pitched whining or whirring sound during acceleration; Noise increases with engine load and vehicle speed; Sound originates from transmission area; Noise stops when accelerator is released; Noise progressively worsens over time; No warning lights or dashboard alerts
Repairs/costs cited: Full transmission replacement quoted between $6,000–$13,000 (most commonly $8,000–$9,800). Parts frequently on extended backorder (1–3+ months). Some owners offered 50% coverage by Toyota; most denied warranty assistance due to mileage overages. Replacement transmissions often carry only 1-year warranty.
Recalls/TSBs owners mention: Technical Service Bulletin T-SB-0008-21 issued for whining/grinding noise from UA80E/UA80F transmission. Customer Support Program (ZJC) exists but covers only specific VINs on 2017–2018 models; 2020 models typically excluded. No recall issued for 2020 model year. Toyota generally denies warranty coverage once vehicle exceeds 60,000 miles or 5 years, even if symptoms began within warranty period. Some cases escalated to partial goodwill support after owner pushback.
Transmission slipping, hesitation, and delayed acceleration
Owners report the transmission fails to respond promptly to throttle input, causing unpredictable acceleration, erratic shifting, or delayed gear engagement. Some describe a shudder or vibration between 40–50 mph. This creates dangerous merging situations and loss of propulsion when needed. The condition stems from internal wear related to washer tab failure securing the counter drive gear retaining nut.
When: Begins between 45,000–107,000 miles, with concentrate in the 55,000–80,000 range. Often becomes critical near or after warranty expiration.
Symptoms owners cite: Hesitation or delayed acceleration response; Loss of acceleration when pressing throttle; Erratic or delayed shifting; Shudder or vibration during acceleration or cruising; Unpredictable acceleration behavior; No warning lights or messages
Repairs/costs cited: Full transmission replacement recommended. Quoted $8,000–$10,000. Some independent repairs (e.g., CV joint replacement, transmission rebuild) performed but failures recurred, indicating root-cause misdiagnosis.
Recalls/TSBs owners mention: Toyota acknowledges the defect in Technical Service Bulletins and Customer Support Programs but limits coverage. 2020 models fall outside the published ZJC program scope despite identical UA80 design to 2017–2018 vehicles.
Transmission internal component failure (bearing/gear wear)
Dealership diagnostics reveal internal bearing failure or counter drive gear movement due to washer tab malfunction, leading to gear wear and internal mechanical breakdown. The failure develops silently over time with no dashboard warning, becoming evident only when drivability symptoms emerge or noise becomes audible.
When: Latent failures detected at 59,000–110,000 miles; initial bearing or gear wear likely begins much earlier but is asymptomatic.
Symptoms owners cite: No early warning signs; Internal bearing failure confirmed by dealer inspection; Counter drive gear movement and wear; Whining noise or drivability loss as symptom onset
Codes mentioned: Internal component failure (diagnostic finding, not OBD code)
Repairs/costs cited: Full transmission replacement required; internal repair not feasible. Cost $6,000–$13,000. One case: parts unavailable after 10+ months in dealership possession.
Recalls/TSBs owners mention: Toyota acknowledges known defect in TSB T-SB-0008-21 and prior ZJC program but refuses to extend coverage to 2020 models. One owner's case remained unresolved after 10+ months; another was offered 50% coverage after escalation.
Coolant intrusion and engine block warping (hybrid system)
One narrative (complaint #3) describes catastrophic engine failure on a 2020 Highlander hybrid. After a thermostat failure at 26,000 miles, coolant allegedly entered cylinder #4, causing block warping, cylinder head cracking, and head gasket failure. The failure occurred on cold start with no overheating warnings beforehand, though a check engine light appeared briefly three days prior. This complaint is isolated in the narrative set and distinct from transmission issues, though the vehicle platform is identical.
When: 26,000 miles: thermostat replacement under warranty. ~83,000 miles (5 years old): catastrophic engine failure on cold start. No prior overheating alerts or performance issues.
Symptoms owners cite: Hybrid system shutdown on cold start; Vehicle would not start; Brief check engine light three days before failure (self-cleared); No overheating warnings or dashboard alerts prior to failure; No performance issues in days leading up to failure
Codes mentioned: Check engine light (appeared briefly, cleared)
Repairs/costs cited: Dealership diagnosed coolant in cylinder #4, warped engine block, cracked cylinder head, failed head gasket. Described as 'premature failure' by dealer service report. No repair cost cited; vehicle disabled.
Recalls/TSBs owners mention: Dealership confirmed as 'premature failure.' Manufacturer was made aware; investigator was sent. No recall, coverage, or repair authorization mentioned.
Vehicle rolling away while parked (unintended vehicle motion)
Two narratives (#13 and #15) describe the vehicle moving on its own while parked with the engine off or in park position. In #13, the vehicle rolled forward into the garage after the owner exited and the shift-to-park alarm did not sound. In #15, the vehicle rolled backward in reverse on a sloped driveway, running over the owner's mother and causing injuries. Both cases are on flat or sloped terrain without engine running; root cause remains unclear (potential transmission or parking brake defect).
When: Complaint #13: no mileage stated. Complaint #15: approximately 500 miles.
Symptoms owners cite: Vehicle moves without engine running or throttle input; No shift-to-park alarm or warning; Forward or backward motion while in park; Owner exits vehicle; vehicle then moves
Repairs/costs cited: Complaint #15: Vehicle towed to dealer; no defect found. Complaint #13: Owner corrected situation independently; no repair mentioned.
Recalls/TSBs owners mention: Complaint #15: Manufacturer notified; investigator sent. No defect detected by dealer. No recall or repair information provided. Complaint #13: No manufacturer contact documented.
Synthesized from 118 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 9 most recent
The contact's wife owns a 2020 Toyota Highlander. The contact stated that soon after purchasing a new set of tires, the vehicle made an abnormal rattling sound upon acceleration. The vehicle was taken to a dealer for an oil change and tire rotation, and the contact was informed that no defect was found on the vehicle. As the failure persisted, the vehicle was taken back to the shop, where the…
My 2020 Highlander developed a whining or grinding noise consistent with the Technical Service Bulletin. I took it to a Toyota Dealership for diagnostic and they confirmed the whining and hissing sound. They said it would cost $9,000 to repair. I called Toyota to request a goodwill repair and they denied me. Toyota case number: 251229000423. The car does not feel safe to drive. We worry that at…
Shortly after the powertrain warranty expired, the automatic transmission in my 2020 Toyota Highlander began producing a loud whining/howling noise during normal driving. The noise appears to come from the transmission area and increases with vehicle speed. The issue was not present during the warranty period and began unexpectedly soon after expiration. The abnormal noise raises concerns about…
Highlander transmission broke down around 80,000 miles
Transmission stutters. Only has 32000 miles.
The transmission in my 2020 Highlander XLE needs replacement at 64,000 miles.
The contact owns a 2020 Toyota Highlander. The contact stated while driving at an undisclosed speed and attempting to accelerate, he heard an abnormal sound coming from the engine compartment. No warning lights were illuminated. The vehicle was taken to the dealer, and it was determined that the sound was coming from the transmission however, the dealer was unable to provide a cause for the…
Transmission whines in low gear.
Transmission failure. Noticed whining when driving, took to local Toyota dealership and they diagnosed transmission failure. They quoted $12,000 for transmission replacement and confirmed that this is a known issue with certain years/models of Toyota Highlander. Ours is a 2020.
Had powertrain trouble with your 2020 Toyota Highlander?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2020 Toyota Highlander?
It's a documented issue but not catastrophic. 118 complaints have been filed. Repairs average $2,500 and most owners catch it before it causes a breakdown.
At what mileage does the powertrain typically fail?
Across the 14 complaints that reported odometer mileage, most powertrain failures cluster between 67,000 and 100,100 miles, with the median around 78,000. A quarter of owners report trouble before 67,000; a quarter make it past 100,100. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2020/Toyota/Highlander.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.