This bulletin provides guidance when diagnosing chain slip, judder, shudder, and hesitation concerns on the TR690 model CVT transmissions used in the models listed. (This is an revised version of the original bulletin.)
full bulletin at NHTSA ↗2021 Subaru Ascent powertrain problems
moderate Owners of the 2021 Subaru Ascent have filed 16 NHTSA complaints about the powertrain 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 →
Complaints
16
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2019 Ascent | 80 |
| 2020 Ascent | 54 |
| 2021 Ascent (this page) | 16 |
| 2022 Ascent | 13 |
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.
This Bulletin announces a correction to the diagnostic procedures for certain CVT related DTCs, including P0730, P0746, P0747, P0841, P0846, P0867, P1867, P1894, and P2723.
full bulletin at NHTSA ↗This bulletin announces a design change to the TR690 CVT control valve body which features an enhanced line pressure sensor O-ring, designed to prevent abnormal sensor readings caused by O-ring leakage.
full bulletin at NHTSA ↗This bulletin provides guidance when diagnosing chain slip, judder, shudder, and hesitation concerns on the TR690 model CVT transmissions used in the models listed.
full bulletin at NHTSA ↗This Bulletin announces the release of a new diagnostic assistance application for TR690 CVT-equipped vehicles.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2021 Ascent's CVT transmission shows a consistent pattern of early failure across all 16 complaints. Owners report slipping and hesitation between 15–30 mph and at highway speeds starting as low as 7,600 miles, with some vehicles losing complete motive power at 40,000–80,000 miles. Shuddering and jerking transfer vibration to the steering wheel; cold starts at high elevation bring hesitation; hard clunking from Park to Drive is commonplace at 6,000 miles.
Multiple owners describe no warning lights before failures occur, complicating diagnosis. When dealerships finally identify the problem—usually by finding metal shavings in transmission fluid—replacement is the only option. Costs run $7,000–$11,000 at dealerships, though one independent shop charged $5,400 for a rebuilt unit. One vehicle required three transmission replacements within the first few years of ownership.
The real problem surfaces after repair: replacement transmissions sometimes develop identical shuddering and slipping within 500–3,000 miles. Subaru field techs run diagnostics and send data to Subaru of America but offer no resolution. Warranty coverage varies; some owners get denied outright, while others receive partial goodwill assistance. Owners note that 2019–2020 models had similar issues and received extended coverage to 100,000 miles—coverage that apparently did not extend to the 2021 model year despite identical failure patterns.
Same Subaru Ascent powertrain reports on nearby years: 2019 · 2020 · 2022
Failure modes owners describe
CVT transmission slipping and hesitation
Transmission loses power momentarily or slips under acceleration, preventing the vehicle from accelerating as intended. Occurs most commonly between 15–30 mph and at highway speeds. No warning lights typically present.
When: Reported from 7,600 miles up to 80,000 miles; many failures occur in early ownership (under 60K warranty period, though some occur after)
Symptoms owners cite: Loss of acceleration or inability to accelerate when gas pedal depressed; Transmission slipping sensation; Hesitation in traffic; Intermittent power loss during acceleration
Repairs/costs cited: Transmission replacement cost $7,000–$11,000 at dealership; one owner paid $5,400 for rebuilt transmission at independent dealer; aftermarket fluid replacement ($1,000 noted) temporarily improved condition but did not solve underlying issue
Recalls/TSBs owners mention: Subaru has refused warranty coverage on several vehicles after 60K miles or near warranty expiration, offering only partial goodwill payments ($2,000–$3,000 discounts); some owners referenced potential recalls for 2019–2020 CVT models (100K mile coverage) that may not have applied to 2021 model year
CVT transmission shuddering, jerking, and noise
Transmission shudders, jerks, or makes severe noise when shifting gears or during acceleration/deceleration. Shuddering is severe enough to transfer to steering wheel. Occurs at low and highway speeds. Metal particles found in transmission fluid on inspection.
When: Reported from 6,000 miles through higher mileage; multiple cases show failure patterns within 500–3,000 miles after replacement transmission installed
Symptoms owners cite: Shuddering or jerking sensation during acceleration and deceleration; Hard or odd shifting from Park to Drive; Loud clunking noise when shifting from Park to Drive; Squeaking during cold starts when shifting; RPM fluttering and chugging sounds; Steering wheel shakes from transmission vibration
Codes mentioned: NHTSA TSB 10185089 (referenced in complaint #8; technicians ran protocols but unable to achieve gear-ratio fluctuation in test)
Repairs/costs cited: Metal shavings found in transmission fluid indicating internal wear; transmission reprogramming attempted on one vehicle but failed; replacement transmissions sometimes exhibit same symptoms within 500–3,000 miles
Recalls/TSBs owners mention: Dealerships acknowledge shuddering and document it; Subaru of America receives data from field techs but does not commit to fixes; TSB testing performed but resolution pending; one owner reported Subaru refused extended warranty despite time spent diagnosing
Catastrophic CVT transmission failure
Complete loss of transmission function rendering vehicle inoperable. Vehicle cannot move from Park or Reverse. No warning lights precede failure.
When: Reported at mileage ranging from 40,000 to 80,000 miles; one case shows failure of second transmission after only 13 months and 15,000 miles
Symptoms owners cite: Vehicle jerks and stops when shifting into Reverse or Drive; Complete loss of power transmission; No prior warning lights or diagnostic codes
Repairs/costs cited: Transmission replacement mandatory; costs $10,000+ at dealership; one owner installed rebuilt transmission for $5,400; one owner paid $1,000 for third replacement after second failed at 13 months
Recalls/TSBs owners mention: Subaru of America denied warranty coverage or offered minimal goodwill assistance; one owner had transmission replaced three times within warranty period, paying $1,000 on third replacement; vehicle ultimately sold/disposed of by owner
CVT transmission darkened/degraded fluid requiring early replacement
CVT fluid darkens prematurely and degrades well before manufacturer service interval (66,000 miles), indicating internal wear and contamination. Fluid inspection at independent shop showed need for replacement.
When: Noted after approximately 60,000 miles at one location (8,000 feet elevation); timeline suggests early degradation
Symptoms owners cite: Cold start hesitation and jerking when accelerating at high elevation; Dark transmission fluid on inspection
Repairs/costs cited: Fluid exchanged with OEM equivalent (non-Subaru brand) at independent ASE-certified shop; transmission function improved temporarily, then declined again with jerking symptoms
Recalls/TSBs owners mention: No manufacturer response documented for this failure mode; dealership had inspected CVT fluid at 36,000-mile service but did not identify degradation
Synthesized from 16 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
The transmission/CVT component on the vehicle, 2021 Subaru Ascent is malfunctioning. When being driven, the malfunctioning transmission will cause the vehicle to hesitate in traffic, as well as feeling the slippage of the transmission when in motion. The vehicle also has a burning odor when being driven. NYS inspection was conducted on 10/27/25. The transmission malfunction has been confirmed…
Car has always refused to accelerate if gas pedal is pushed down too quickly. Just before 60K miles, on way home we had pulled over at a roadside stop on a hill. Tried to pull across highway to continue up road, car refused to accelerate and luckily were able to brake in time to keep from getting t-boned by big truck heading down the hill. No trouble lights came on, so weren't sure if this was…
When operating the 2021 Ascent, I experience intermittent problems at various shift-points in the CVT and at various RPMs. The transmission seems to shudder and slip between shift-points, and the shuddering sensation is so severe that it transfers up through the steering column and the steering wheel shakes. I have brought the vehicle to my dealership (Kocourek Subaru in Wausau), and they have…
Had powertrain trouble with your 2021 Subaru Ascent?
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 Subaru Ascent?
It's a documented issue but not catastrophic. 16 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?
Based on the 16 complaints filed, powertrain issues most often appear around 75,000 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
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/Subaru/Ascent.
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.