This preliminary informational (PI) bulletin provides information to dealership personnel that may be helpful when addressing underbody component corrosion with customers.
full bulletin at NHTSA ↗2020 GMC Acadia powertrain problems
moderate Owners of the 2020 GMC Acadia have filed 19 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
19
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2016 Acadia | 20 |
| 2017 Acadia | 227 |
| 2018 Acadia | 155 |
| 2019 Acadia | 145 |
| 2020 Acadia (this page) | 19 |
| 2021 Acadia | 15 |
| 2022 Acadia | 4 |
| 2023 Acadia | 9 |
| 2024 Acadia | 6 |
When does it fail?
Of the 19 powertrain complaints filed for the 2020 GMC Acadia, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 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 20% of all owner complaints filed against this vehicle, across 7 categories tracked.
No new NHTSA powertrain complaint has been filed on this vehicle in over 3 years — the issue may be aging out of the active population.
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 provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2.
full bulletin at NHTSA ↗This service bulletin provides information on the harmful effects of ethylene glycol in transmission fluid.
full bulletin at NHTSA ↗This service bulletin provides 9th gear operation information to respond to customers that may comment on transmission shift operation.
full bulletin at NHTSA ↗This service bulletin advises the tech that the rotational Clicking Noise Heard After Engine Shut Down may be normal characteristics of the vehicle.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2020 GMC Acadias report pervasive and serious powertrain failures across transmission, engine control, and electrical systems. The 9-speed transmission emerges as the primary concern: shuddering at specific speeds (35–45 mph noted repeatedly), complete loss of drive, inability to shift into or hold drive, and torque converter failure—often within the first 15,000 miles or by 84,000 miles on regularly serviced vehicles. One owner paid ~$12,000 for transmission replacement; GM covered all but ~$3,600 out of pocket. A dealership confirmed stocking thermostat parts because failure is common on this model.
Vehicle-immobilizing failures also occur: one owner's vehicle dropped into neutral and would not re-engage park after a July 2022 software update, stranding them with two infants. The dealership couldn't diagnose because the vehicle wouldn't start.
Thermostat failures trigger check-engine lights with no advance warning at 74,000–84,000 miles (~$1,500 repair). Separate issues include sensor faults (P0014 VVT codes that persist after replacement), stalling during auto-stop engagement on inclines, rear-view camera dropout, and erratic shift behavior where the vehicle shifts out of drive without driver input.
One owner notes GM acknowledged known defects and issued recalls for 2019–2020 Acadia transmissions related to missing bolts in the start-stop accumulator endcap, but their 2020 reportedly does not qualify. Owners report dealerships were "dismissive" initially, and warranty denials occurred when mileage exceeded limits despite earlier documented reports.
Same GMC Acadia powertrain reports on nearby years: 2017 · 2018 · 2019 · 2021
Failure modes owners describe
Transmission Failure (Complete Loss of Drive / Slipping / Shuddering)
The 9-speed transmission fails completely or partially, resulting in sudden loss of motive power, inability to shift, torque converter shuddering, and erratic shifting behavior. Owners report the transmission slipping, shuddering at various speeds, refusing to shift properly, and in severe cases losing drive entirely while moving.
When: Reported from 15,000 miles up to 84,000 miles; some owners note failures within first year of ownership despite regular maintenance and low mileage.
Symptoms owners cite: Transmission shuddering or bucking at specific speeds (35–45 mph range noted); Loss of motive power while driving; Vehicle refuses to shift into drive or reverse, or shifts out involuntarily; Hard shifting after software updates; Torque converter vibration and noise; Service Transmission warning messages; Unable to Shift Gears message display; Dark transmission fluid; Rough shifting with delayed engagement
Codes mentioned: Service Vehicle, Unable to Shift Gears, Service Transmission
Repairs/costs cited: Torque converter replacement (initial diagnosis) or full transmission replacement required. One owner quoted ~$12,000 for transmission replacement; GM covered all but ~$3,600 out of pocket. Transmission fluid flush performed without resolving issue.
Recalls/TSBs owners mention: GM has acknowledged known defects and issued recalls for 2019–2020 Acadia transmissions related to missing bolts in the start-stop accumulator endcap, which can cause fluid leaks and lead to torque converter/transmission failure. Some owners reported GM initially denied warranty coverage when mileage exceeded limits, even if issue was reported before that threshold.
Shift-to-Park Malfunction
Vehicle cannot engage park mode and automatically drops into neutral. The neutral button flashes, and the in-vehicle and mobile app display 'Shift to Park' alerts. Vehicle becomes immobilized and cannot be turned off safely.
When: Reported after a July 2022 software update; approximately 47,204 miles (within 60,000-mile warranty window).
Symptoms owners cite: Vehicle automatically goes into neutral while in park; Neutral button flashing; In-vehicle and mobile app alert: 'Shift to Park'; Vehicle cannot be placed in or held in park; Vehicle will not turn off; Hard shifting observed after the same software update
Repairs/costs cited: Dealership unable to diagnose because vehicle would not turn over after battery was disconnected to address the immobilization hazard. Vehicle remained at dealership for ~2 weeks with no resolution.
Recalls/TSBs owners mention: Dealership initially stated inability to confirm warranty coverage for the 60,000-mile powertrain warranty because the vehicle could not be started for diagnostic verification. Recalls for 'Shift to Park' error exist for 2019 model year and earlier; 2020 does not appear to be included.
Thermostat Failure
Thermostat fails without warning, triggering check engine light and loss of engine control. One dealer reported keeping thermostat parts in stock because failures are common on Acadias.
When: Reported at 74,000–84,000 miles; one owner notes 'no warning lamps or symptoms before failure.'
Symptoms owners cite: Check engine light illumination; No advance warning signs
Codes mentioned: Check engine light (specific codes not provided)
Repairs/costs cited: Estimated at ~$1,500 per repair. Dealership confirmed the failure is common enough to stock thermostat parts regularly.
Recalls/TSBs owners mention: GM covered 100% of timing cover replacement (found defective during same thermostat repair event). Warranty coverage status for thermostat repair not specified in narrative.
Timing Cover Defect
Timing cover fails, discovered during transmission repair diagnosis. Owner notes this was a defective component found concurrent with transmission failure.
When: Identified during transmission repair at 74,000 miles; no independent timeline given for when it initially failed.
Symptoms owners cite: No symptoms reported; found only during diagnostic workup for transmission failure
Repairs/costs cited: Repair performed; costs not separately itemized.
Recalls/TSBs owners mention: GM covered 100% of timing cover replacement.
Reduced Driver Assist / Thermostat-Related Electrical Fault
Vehicle displays 'Driver Assist is reduced drive' error message, shuts down the engine, and activates the parking brake. Owners later diagnosed with thermostat failure. The condition recurs repeatedly and dealerships initially struggle to identify the root cause.
When: Reported at 50,000+ miles; errors escalate over time until finally diagnosed as thermostat at higher mileage.
Symptoms owners cite: Error message: 'Driver Assist is reduced drive'; Engine shut-down while driving; Parking brake activates automatically; Recurring failures despite multiple dealer visits; OnStar diagnostics unable to detect issue initially
Codes mentioned: Driver Assist error code
Repairs/costs cited: Final diagnosis: thermostat failure requiring ~$1,600 repair. GM did not cover under warranty once mileage exceeded coverage limit, even though issue was reported and documented prior to mileage threshold.
Recalls/TSBs owners mention: GM declined warranty coverage citing mileage over limit at time of final diagnosis, despite OnStar record of the issue occurring earlier.
VVT Sensor Failure (P0014 Code)
Variable Valve Timing (VVT) sensor throws P0014 diagnostic code repeatedly. Owner has replaced the sensor multiple times with no resolution; wiring checked with no damage found. Multiple online complaints and recalls noted for the same issue, but owner's VIN does not return any recalls.
When: Not specified; owner notes multiple complaints and recalls exist online for the same issue on 2020 Acadia 3.6L V6.
Symptoms owners cite: P0014 code (VVT sensor fault); Persistent code return after sensor replacement
Codes mentioned: P0014
Repairs/costs cited: Owner replaced VVT sensor and checked wiring for damage (none found); issue persists. No successful repair documented.
Recalls/TSBs owners mention: No recall found when VIN queried despite owner noting multiple complaints and recalls existing online for the same failure on the same model.
Rear-View Camera Malfunction
Rear-view camera cuts in and out repeatedly, creating safety hazard. System update did not resolve the issue.
When: Not specified in narrative.
Symptoms owners cite: Rear-view camera intermittent/cuts in and out; Near-accident risk reported
Repairs/costs cited: System update attempted without success; no repair described.
Stalling / Loss of Power During Auto-Stop (Start-Stop System)
Vehicle stalls or fails to restart when the automatic stop-start system engages, particularly when stopped at traffic lights or on inclines. Hard jerk/lurch upon restart. Vehicle also loses power randomly, triggering powertrain warning lights and fuel system codes.
When: Not specified; one incident noted on uphill incline during stop.
Symptoms owners cite: Vehicle stalls when auto-stop engages; Hard jerk or lurch on restart; Random loss of power while driving; Powertrain warning light illumination; Fuel-related engine codes; Loss of acceleration response after restart
Codes mentioned: Powertrain code (specific code not provided), Fueling code
Repairs/costs cited: Dealership replaced a sensor under warranty; owner reports issue persists despite repair. No successful permanent fix documented.
Recalls/TSBs owners mention: Sensor replacement performed under warranty; issue not resolved. Dealership reported as 'dismissive' to owner's concerns.
Transmission Control Valve Issues / Unintended Shifting
Vehicle exhibits erratic shift behavior including unintended downshifts, upshifts out of drive, and inability to remain in selected gear. RPM spikes without pedal input; vehicle lurches forward or shifts out of drive involuntarily while driving, creating safety hazard.
When: Not specified in narratives; one incident occurred at highway merge.
Symptoms owners cite: Unintended downshifts while driving; Vehicle shifts out of drive involuntarily, leaving driver without power; RPM spikes without accelerator input; Lurching forward upon acceleration after hesitation; Vehicle won't remain in selected gear; Auto-shift to park when attempting to place in drive or reverse
Codes mentioned: Unknown warning light
Repairs/costs cited: Transmission replacement recommended at independent mechanic; not repaired in one case.
Recalls/TSBs owners mention: One owner reports vehicle is not on the recall list despite using 'all the same parts' as vehicles that are recalled.
Hesitation / Lack of Acceleration Response
Vehicle hesitates or fails to respond when depressing the accelerator pedal from a complete stop or at various speeds. Delays in power delivery create safety concerns.
When: Reported at various mileage points; one incident at ~80,000 miles.
Symptoms owners cite: Hesitation on acceleration from complete stop; Delayed power delivery at various speeds; Engine revving without accelerator input; Unintended downshifts during hesitation
Codes mentioned: Unable to Shift Gears, Service Vehicle
Repairs/costs cited: One case scheduled for dealer diagnostic with no results reported.
Electrical System Anomalies (Stalling, Loss of Control, Multiple Warning Lights)
Vehicle experiences sudden electrical system failures resulting in stalling, loss of motive power, anti-theft activation, spontaneous liftgate opening, and multiple unrelated warning lights and messages. Failures cannot be duplicated by dealership, and warranty has expired.
When: Reported at approximately 2,000 miles (early in vehicle ownership); multiple instances.
Symptoms owners cite: Vehicle stalls while driving at undisclosed speed; Anti-theft system warning light illuminates; Loss of motive power; Vehicle fails to restart; Buzzing noise from engine compartment during start and driving; Alarm chimes (cause unknown); Liftgate opens independently; Multiple unrelated warning lights; Unknown warning messages displayed
Codes mentioned: Anti-theft system warning light
Repairs/costs cited: Vehicle towed to dealer; cause of failure could not be duplicated. Vehicle not repaired.
Recalls/TSBs owners mention: Warranty had expired; manufacturer was not notified of failure.
Low-Speed Power Loss and Jerking
Vehicle loses power at low speeds and jerks erratically. Brake light illuminates during events.
When: Not specified.
Symptoms owners cite: Loss of power at low speeds; Jerking motion; Brake light illumination during event
Synthesized from 19 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 4 most recent
I started receiving an error message that driver assist is reduced drive with car at 50k miles (i have an onstar diagnostic report and phone call made that day). It shut my car down and activated the parking break. I called Onstar at that moment it happened and they found nothing wrong with the car. It continued to happened several times after and each time I took it to the dealer they were…
The contact owns a 2020 GMC Acadia. The contact stated while stopped at a traffic light and depressing the accelerator pedal after the light had changed, the vehicle hesitated and then lurched forward. The contact stated that an unknown warning light was illuminated. The contact stated that while driving at an undisclosed speed, the vehicle was vibrating abnormally. The vehicle was taken to an…
2020 GMC acadia. Consumer writes in regards to loss of power at low speeds and jerking with brake light illuminated. *ld *js
I own a 2020 GMC Acadia that has experienced multiple major mechanical failures within one year. In January 2025, at around 74,000 miles, the transmission failed completely with no warning or clear indication of what was wrong. The vehicle suddenly lost power while driving, creating a safety risk for me and my child. I was quoted around $12,000 for the transmission replacement initially before…
Had powertrain trouble with your 2020 GMC Acadia?
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 GMC Acadia?
It's a documented issue but not catastrophic. 19 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 19 complaints filed, powertrain issues most often appear around 40,775 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/2020/GMC/Acadia.
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.