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 ↗2021 Toyota Highlander powertrain problems
moderate 170 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Failure mileage
Complaints
170
Recalls
0
Avg fix
$2,500
2crashes
When does it fail?
Of the 170 powertrain complaints filed for the 2021 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 38% of every owner complaint on file for this vehicle — the dominant problem area across 11 categories tracked.
Owners have filed 170 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.
TSB: Some 2021 model year Avalon, Highlander, and Camry vehicles equipped with UA80E or UA80F transmissions may exhibit a whine or grind noise from the transmission. This condition may be caused by an issue with the front carrier assembly pinion shafts. Follow the Repair Procedure in this bulletin to address this condition.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2021 Toyota Highlanders consistently report identical transmission failures tied to Toyota Technical Service Bulletin T-SB-0008-21, issued February 9, 2021. The most common symptom is a high-pitched whining, grinding, or buzzing noise that begins during acceleration, increases with vehicle speed, and subsides when the driver releases the throttle. This noise typically emerges between 50,000 and 90,000 miles—often around 60,000–75,000 miles—after most owners have already exceeded Toyota's 5-year/60,000-mile powertrain warranty window.
Owners report that Toyota dealerships confirm the noise stems from internal wear in the front carrier assembly pinion shafts within the UA80E or UA80F 8-speed automatic transmission. The only remedy is complete transmission replacement, quoted at $7,500–$11,500. Replacement transmissions are on extended backorder nationwide, with wait times stretching 3–6 months or longer. Some owners experienced additional complications after transmission replacement, including electrical failures and head gasket or transfer case issues.
Notably, the TSB was released 50 days before some vehicles were sold to consumers, yet owners were not notified of the known defect at purchase. Dealership technicians explicitly confirm this is a "known issue" affecting numerous 2021 Highlanders, yet no formal recall has been issued. Many owners feel the problem represents a design or manufacturing defect that Toyota should cover, particularly given Toyota's track record of extending transmission warranties on earlier model years (2016–2019) for similar UA80 transmission failures.
Same Toyota Highlander powertrain reports on nearby years: 2018 · 2019 · 2020 · 2022 · 2023
Failure modes owners describe
UA80E/UA80F Transmission Whining/Grinding Noise — Front Carrier Assembly Pinion Shaft Wear
Internal transmission wear in the front carrier assembly pinion shafts causes high-pitched whining, grinding, or buzzing noise that increases with acceleration and vehicle speed, then subsides when throttle is released. Noise typically emerges between 50k–90k miles. Diagnostic fluid checks show metal shavings in some cases. Toyota Technical Service Bulletin T-SB-0008-21 (issued Feb 9, 2021) identifies this condition and prescribes complete transmission replacement as the only remedy.
When: 50,000–90,000 miles; most commonly 60,000–75,000 miles; typically 3–4 years into ownership
Symptoms owners cite: High-pitched whining, grinding, or buzzing noise during acceleration; Noise increases with vehicle speed and throttle pressure; Noise subsides when foot released from accelerator; Metal shavings visible in transmission fluid in some cases; Noise first observed at moderate speeds (25–50 mph)
Codes mentioned: No diagnostic trouble codes present in most cases, Vehicle computer diagnostics return no transmission-related faults
Repairs/costs cited: Complete transmission replacement required; no internal repair option. Replacement transmissions quoted $7,500–$11,506; remanufactured units also carry identical failure risk. Parts on extended backorder (3–6 months+ wait times reported). Labor typically 3–4 days installation.
Recalls/TSBs owners mention: Toyota Technical Service Bulletin T-SB-0008-21 (Feb 9, 2021) acknowledges defect; covers select VINs only; coverage limited to 5-year/60,000-mile powertrain warranty; no formal recall issued; extended warranty programs often deny claims outside mileage/time limits; some owners denied goodwill assistance despite warranty coverage
Transmission Jerking, Hard Shifts, and Hesitant Acceleration
Automatic transmission exhibits abnormal shifting behavior including jerky or chunky gear changes, hard shifts with lurching, hesitation when accelerating from stop, and delayed engagement. Symptoms progress over time and often accompany whining noise. Some owners report transmission slipping between gears or hunting for correct gear.
When: Early in ownership (20,000 miles reported); progresses to failure between 50,000–115,000 miles
Symptoms owners cite: Jerky, chunky, or hard shifts during acceleration or deceleration; Hesitation and delayed gear engagement; Lurching when shifting from stop or at low speeds; Transmission slipping between gears; Gear hunting (transmission cannot settle on correct gear); Surging or bucking sensation while driving
Codes mentioned: No warning lights or diagnostic codes in most reported cases, Dealership computer diagnostics show no faults
Repairs/costs cited: Transmission replacement; no software updates or adjustments resolve symptoms. One owner reported replacement with remanufactured unit that continued exhibiting identical surging/bucking at 10k miles post-repair.
Recalls/TSBs owners mention: Early symptoms dismissed as 'normal break-in' by dealers; dealership technicians acknowledge known issue but offer only replacement as remedy; TSB T-SB-0008-21 applies to select VINs only; warranty denial once owner mileage exceeds 60,000 miles
Transmission Failure — Sudden Loss of Power or No-Start Condition
Complete transmission failure resulting in loss of motive power, inability to shift into drive or reverse, stalling, or no-start condition. Failure can be sudden with no prior warning or progress from earlier warning symptoms. Some failures occur after service (transmission replacement), introducing secondary electrical failures.
When: 53,000–115,000 miles; failure often abrupt with minimal warning
Symptoms owners cite: Complete loss of forward or reverse drive capability; Vehicle will not shift or respond to transmission commands; Engine stalls or shuts down while driving; Vehicle refuses to start after being turned off; Sudden limp mode activation with flashing warning lights; Vehicle coasts to stop and becomes immobile
Codes mentioned: Multiple warning lights may illuminate (check engine, low oil pressure, hybrid system malfunction in some cases), No DTCs recorded in some cases despite complete failure
Repairs/costs cited: Complete transmission replacement required; cost $7,500–$11,500. In one case, replacement transmission led to head gasket failure and transfer case failure, requiring additional repairs. Parts shortages extend repair timelines to 2–6 months; vehicle stranded throughout repair period.
Recalls/TSBs owners mention: Manufacturer notified in some cases but repair denied under warranty once mileage exceeds 60,000 miles or time exceeds 5 years; some owners offered extended warranty programs at additional cost ($4,500 reported); no recall issued
Post-Transmission-Replacement Electrical and Mechanical Failures
After dealership transmission replacement, vehicle develops new electrical issues (dashboard warning lights, system alerts, loss of reverse function, battery drain) and mechanical issues (rattling noise, fluid leaks from head gasket and transfer case) that were not present prior to repair. Dealership provides inconsistent diagnoses and lacks written documentation.
When: Immediately following transmission replacement; ongoing after repair
Symptoms owners cite: Loss of reverse function post-repair; Battery drain shortly after transmission repair; Dashboard warning lights and system alerts flashing during remote start; Rattling noise from undercarriage; Transmission fluid leaking post-repair; Head gasket failure and fluid leaks; Transfer case failure post-repair
Codes mentioned: Multiple warning lights present but exact fault codes not specified by owners, Dealership diagnostics cite catalytic converter but do not explain electrical failures
Repairs/costs cited: Dealership has inspected multiple times without resolving issues; no written diagnostic reports provided despite owner requests; repair costs estimated but not detailed; vehicle safety compromised by unpredictable electrical behavior
Recalls/TSBs owners mention: Manufacturer made aware; dealership provided changing diagnoses; no resolution provided despite multiple visits; parts and root causes not clearly identified to owner
Transmission Noise Misattributed to Unrelated Components
Owners report transmission whining/grinding noise to dealership technicians, who initially misdiagnose the sound as originating from other components (front hub assembly, bearings, brake system). Owners undergo unnecessary repairs for these unrelated parts before transmission is correctly identified as the source.
When: Variable; misdiagnosis can occur early in ownership
Symptoms owners cite: High-pitched noise attributed to front hub assembly or bearing by initial diagnosis; Noise continues after unrelated component replacement; Vibration sensation mistaken for suspension or bearing issue; Multiple dealership visits required before transmission correctly identified
Repairs/costs cited: Owners incur repair costs for replacement of misdiagnosed components (front driver-side hub assembly replacement reported); transmission still requires replacement after unrelated parts are replaced
Synthesized from 170 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 8 most recent
The contact owns a 2021 Toyota Highlander. The contact stated that while driving at various speeds and depressing the accelerator pedal, the contact heard an abnormal whining sound coming from the front of the vehicle. The vehicle was taken to an independent mechanic, where the contact was informed that it was a known failure. The vehicle was then taken to the dealer, where it was diagnosed, and…
I have a faulty transmission that is now widely known. 2021 Highlander with the UA80 transmission. Out of warranty and Toyota wants to provide no help even know this is an ongoing issue with so many owners
My transmission started to make whining noise took to the dealer to check they confirmed it was a transmission issue that it needed to be replaced. After doing some digging I came across a toyota service bulitin that claimed this issue only affected a batch of vehicles. ( T-SB-0008-21 ) I have searched on forums and found out that a lot of people are haveing the same issue and Toyota is not doing…
I purchased my new 2021 Highlander in Sept. of 2021. At about 88K miles, my car started making a whining or buzzing noise when accelerating. I am scheduled to take my highlander to the dealership to be looked at, but in the meantime, research on multiple forums and NHTSA -this is found to be a common issue with the 2021 toyota highlander transmission. Upon further research, I discovered that…
The transmission has developed a transmission whining noise which Toyota has released a TSB 0008-21. My vehicle has 104,000 miles and is now out of warranty. If this is a known defect on many Toyota vehicle models a transmission replacement should be free if no longer in warranty.
The Highlander only have 62000, miles and still has a new car smell ,but it need a transmission was told by service advisor that it could stop in the middle of the of traffic with no warning no engine light on dash nothing upon further research a lot of customers are having the same problem Please help Toyota has been my brand since 1996 and I’m sad that the don’t stand behind the brand for such…
Transmission went out at 94,000 mils. Loud whinning noise and vechicle very loud sounds like a disel truck once cranked.
I purchased my new 2021 Highlander in Sept. of 2021. At about 70K miles, my car started making a whining or buzzing noise when accelerating. I took it to the Toyota dealership in Fort Collins, CO. They told me my transmission is failing. They stated I needed completely replaced for just a few dollars under $8000. They stated that the Highlander transmissions are on backorder for replacement.…
Had powertrain trouble with your 2021 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 2021 Toyota Highlander?
It's a documented issue but not catastrophic. 170 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 8 complaints that reported odometer mileage, most powertrain failures cluster between 54,000 and 74,700 miles, with the median around 60,347. A quarter of owners report trouble before 54,000; a quarter make it past 74,700. 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/2021/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.