2021 Acura TLX Powertrain (other) Problems

I am submitting this complaint regarding a transmission failure involving my 2021 Acura TLX, which I believe presents a significant motor vehicle safety defect. The transmission experienced a premature and unexpected failure that resulted in a substantial reduction in vehicle performance, including a loss of power delivered to the rear wheels and a corresponding reduction in vehicle directional control. At the time of the failure, the vehicle's handling characteristics changed unexpectedly, creating a potentially hazardous operating condition. The loss of rear-wheel power adversely affected the vehicle's stability and responsiveness, particularly during acceleration, lane changes, and other driving maneuvers where predictable vehicle control is necessary for safe operation. This condition significantly increased the risk of a crash and exposed both the vehicle occupants and the motoring public to an unreasonable safety hazard. Upon researching this issue, I discovered that transmission failures and related drivetrain defects have been reported by other owners of 2021 Acura TLX vehicles. The existence of multiple similar complaints suggests that this may not be an isolated incident but rather a recurring defect affecting this vehicle model and year. The failure occurred despite the vehicle being maintained in accordance with manufacturer recommendations and without any misuse or modification that would reasonably contribute to such a catastrophic drivetrain failure. A transmission component that affects vehicle propulsion and directional control should not fail under normal operating conditions. Given the nature of the defect and its direct impact on vehicle safety, I respectfully request that the National Highway Traffic Safety Administration investigate this issue to determine whether a broader safety-related defect exists within the 2021 Acura TLX population. If such a defect is confirmed, Acura/Honda should be required to provide an appropriate remedy.

NHTSA ID

11776228

Incident

Nov 3, 2026

My car shakes and rocks like a boat over every bump and when i make turns the car dips really bad and bounces around. It’s been doing this since i got the car and purchase a warranty i could not use from sports Mazda. Its unsafe at high speeds and jerks when switching lanes. I continuously do the alignment every 2-4 weeks. And the toe gets adjusted and it goes right back to the issue. Acura told me this is how their cars drive and it feels unsafe to drive

NHTSA ID

11774579

Incident

Aug 30, 2025

VEHICLE LOSING TRACTION WHILE DRIVING. CONFIRMED BY [XXX]'S ACURA IN [XXX]. CONFIRMED: TRANSFER CASE WITH BAD TRANSMISSION. VEHICLE NOW INOPERABLE. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11771884

Incident

Sep 8, 2026

I am submitting this complaint regarding a major drivetrain failure in my 2021 Acura TLX Type S SH-AWD with approximately 86,643 miles. My vehicle experienced a complete loss of AWD. The front two wheels are receiving power, but the rear wheels are no longer receiving power. An independent mechanic initially diagnosed a transfer-case/drivetrain failure and advised that the transmission may also be involved. I then took the vehicle to OH Acura of Temecula, where the Acura dealership independently diagnosed the vehicle with transmission and transfer-case failure. The service manager confirmed that my independent mechanic’s diagnosis was accurate. The dealership provided a repair estimate of approximately $16,000. I am concerned because NHTSA previously opened investigation DP26-001 regarding reported failures involving the transmission and transfer case in 2021–2023 Acura TLX SH-AWD vehicles. My vehicle is now experiencing a complete loss of AWD consistent with the issue described in that investigation. I also experienced an unusual grinding noise on September 21, 2026, which lasted approximately five minutes before stopping. I was subsequently told the noise was caused by worn spindles. The noise has not returned, and I am not claiming that issue was related to the drivetrain failure. Acura declined goodwill assistance, citing lack of documentation for transmission maintenance. The vehicle is outside its original warranty. I am submitting this complaint so NHTSA has a record of my vehicle’s actual failure and complete loss of AWD and can consider it alongside other reports involving this vehicle and drivetrain configuration. I can provide the VIN, dealership diagnosis, repair estimate, and supporting documentation if requested.

NHTSA ID

11768412

Incident

Oct 1, 2026

The transfer case and transmission splines have been stripped causing the car to be FWD only. The issue was confirmed by the dealer, and both the transfer case and transmission were replaced under warranty. The car shuddered, followed by a drivetrain noise for a few seconds. No warning lights or messages appeared when the incident occurred. The issue occurred at approximately 26,574 miles on the odometer.

NHTSA ID

11760565

Incident

Aug 17, 2026

transfer case leaking fluids at 73,000 miles

NHTSA ID

11759768

Incident

Aug 26, 2026

Transmission and transfer case failure. Noticed a very small amount of fluid leaking and took to dealership. Dealer informed me that I was "lucky" to have noticed and that the transfer case spline failure had occurred. Notified that the problem could lead to sudden loss of all wheel drive and loss of vehicle control, vehicle slipping, and oversteer. DP26001 had indicated that these issues are a safety concern and could lead to an accident. I had noticed instability in certain issues where the rear of the car did not feel firmly planted when cornering (oversteer). Dealer indicated that both the transmission and transfer case need to be replaced. I was ~8000 miles within powertrain warranty. Parts are on a national backorder which indicates a widespread issue. No warning lamps or indication of seal failure that leads to stripped splines off the shaft due to the fluid leak. NHTSA does not understand how the Acura SH-AWD system interacts with vehicle dynamics and handling, and loss of the rear wheel drive and its impact on oversteer would be absolutely NO DIFFERENT than a rear sway bar breaking under load while cornering. I experienced this exact symptom on [XXX] where the road goes from 3 lanes to 2 lanes on a sweeping right hand curve. This is where I had felt like I may lose control of the vehicle, the rear of the car started to come around and I had to steer into the slide to regain control of the vehicle. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11758705

Incident

Aug 14, 2026

I'm losing power than normal all of a sudden. When I step on the gas after light hits green in sport and sport plus mode my car losses traction even when traction control is on, and I hear a loud clunck sound. After the the loud clunck sound the car losses RPM while driving I step off the gas and step back on it and the RPM goes back to normal again.

NHTSA ID

11754848

Incident

Aug 4, 2026

I took this vehicle to get serviced in the summer of 2025. I recently joined an Acura Type S (2021+) group on Facebook and learned that the issue is quite prevalent. I had to have the transmission and transfer case replaced due to transmission issues and traction issues

NHTSA ID

11750163

Incident

Jul 5, 2025

On July 7th 2026 I was driving home, came to a stop light at normal speed, when the light turned green I took off at normal speed and I heard a huge cluck / bang from underneath the car and it bogged and didn’t want to move. I then stepped on the gas because of the Car behind me getting to close and my traction control light started to flash and the car started to shake and feel very uncomfortable to drive . After that I realize only the two front wheels of the car were working and even at low cruising speeds the car feels very unsafe and shakes and hear noises I never heard before the part that is causing this is the transfer case and transmission thus there are many other people who have had this same issues ranging from 21 to 23 tlx type s with 15k miles to 100k miles

NHTSA ID

11748958

Incident

Jul 7, 2026

Transmission splines went out and transfer case has also failed which is only sending power to front wheels

NHTSA ID

11748927

Incident

Jul 6, 2026

On 07/01/2026, at approximately 8:00 AM, during steady acceleration, flashing of MIL with loss of power presented northbound after merging from 235 west bound to I-135 north bound near Park City, KS. Particularly dangerous resulting in near rear end collision. Upon taking nearest exit ramp, attached BlueDriver .OBD II reader, and fault code P0303 - Cylinder 3 Misfire and U0401-68 PGM-Fi/ECM/PCM system event code was logged, with multiple warning indicators that safety system, AWD, brake, and other systems were disabled. Note, vehicle has had TSB 20-053 update w/ flash of PGM-Fi which did not resolve the fault, fault associated with hot and humid climates or period of rain fall, apparent water vapor, condensate build up in intercooler. For Honda Accord and Acura RDX w/ 4 cylinder 2.0 TDGI engine TSB includes redesigned intercooler replacement, that is not available for TLX 21-25 which is currently out of production. This has occurred previously during humid and hot weather, but no intermittent flashing MIL does not store code. Thankful in this instance P0303 and U0401-68 code is stored, and scheduling service at dealership to diagnose misfire.

NHTSA ID

11747673

Incident

Jul 1, 2026

2021 Acura TLX Type S SH-AWD. Total mechanical failure of PTU/transfer case spline interface at 29,800 miles within factory powertrain warranty. Vehicle operated silently in FWD-only with no warning lights, no fault codes, and no dashboard alerts — consistent with all complaints cited in NHTSA Defect Petition DP26001 (opened March 6, 2026, NHTSA #11712885). Failure confirmed by dealer via lift test: propeller shaft and rear wheels stationary while fronts spun. During actuator test, Check AWD System light illuminated for the first time — because the lift removed road-induced wheel rotation that had masked the failure from the ECU throughout normal driving. This is the only condition under which this failure mode is electronically detectable. Dealer replaced transmission (remanufactured ATR kit) and PTU under warranty. Repair took 38 days. CRITICAL-THIRD PTU REVISION: Replacement PTU installed was part #29000-5YK-070. Known revision history: -050 (original, confirmed failure part) → 060 (revised ~2022) → 070 (installed June 2026). The 070 does not appear in any public OEM parts database. Acura has now revised this component three times with zero TSBs, zero public disclosure of engineering changes, and no recall. The 070 revision appearing after DP26001 opened in March 2026 suggests a silent root cause fix while avoiding formal recall obligations. CRITICAL-DPSM GOODWILL CLAUSE: Acura required acceptance of "One Time Goodwill Authorized by DPSM" as condition of repair. This was a warranty obligation, not a goodwill gesture. This clause was imposed while DP26001 is under active federal review, before factory warranty expires, with no confirmed root cause fix. If the 070 part fails again, this clause may be used to deny future warranty coverage. Requesting: (1) complaint added to DP26001 record; (2) Acura compelled to disclose engineering changes between part numbers 050, 060, 070; (3) investigation of DPSM Goodwill clause as systematic pre-recall liability limiation

NHTSA ID

11743423

Incident

Apr 28, 2026

I am submitting this complaint in reference to NHTSA Defect Petition DP26001, opened March 6, 2026, investigating loss of all-wheel drive capability in 2021-2023 Acura TLX vehicles due to interfacing spline failure between the transmission and the power takeoff unit (transfer case). I am the owner of a 2021 Acura TLX SH-AWD with 55,300 miles. I purchased this vehicle on June 2nd, 2026. I have not yet experienced a failure, but I am registering as an affected vehicle owner given the known defect pattern documented in DP26001 and consistent with the 137,329-vehicle population identified in the NHTSA investigation. The failure mode as described in DP26001 involves stripping of splines at the transmission-to-PTU junction, resulting in sudden and complete loss of rear-wheel drive without warning lights or dashboard indication. Documented repair costs for this failure range from $5,000 to $19,000 depending on extent of damage. I am registering this complaint to be included in the documented owner population should the petition escalate to a formal defect investigation or recall. I request notification of any recall action, extended warranty coverage determination, or technical service bulletin issued for this failure pattern.

NHTSA ID

11741697

Incident

Jun 2, 2026

Transfer case failure. I was driving my 2021 Acura TLX Type S when I suddenly heard a loud pop from underneath the car. Right after that, the SH AWD system stopped working and the car was only driving in front wheel drive. There were no warning lights or signs before it happened, due to it being a mechanical failure and not an electrical one because the car does not have sensors for the transfer case. After getting it checked out, I was told the splines between the transfer case and transmission were stripped. I’ve also seen that a lot of other 2021 to 2023 TLX Type S owners have had the same problem. It’s concerning because the AWD system failed out of nowhere, especially since the car depends on it for traction and stability. The car now needs a new transfer case and possibly more drivetrain repairs. (Proof shown in pdf down below, only front wheels spinning)

NHTSA ID

11739426

Incident

May 18, 2026

I drive a 2021 Acura TLX 2.0 L turbo 4 cylinder. I was driving to work on [XXX] on a busy street in Boyle Heights, Ca. When all of sudden I get a warning indicator “engine temp is high do not drive”. Pulled over immediately. Good thing I was in the far right lane and was able to pull over and not stall or get rear ended by another vehicle behind me. There were no warning, symptoms and indicators of the engine's overheating. My vehicle has been in great condition prior with no major or minor issues with my vehicle. We took it to two dealerships for diagnostics. The head gasket blown, empty coolant reservoir, cracked engine block, and other parts of the engine were affected. What if I was on a highway and the car stalled. I could’ve been seriously injured or seriously injured someone else on the road. Acura corporate is aware of our situation and refuse to own their engine safety defects. They want us to pay out of pocket to repair our vehicle. My car is 5 years old there is no way out of nowhere my vehicle should have this type of engine issues. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11739131

Incident

May 6, 2026

Mileage

93,039 mi

Took my car for an oil change and found that the transfer case is leaking its fluid. Known to lead to tranfer case failure.

NHTSA ID

11736683

Incident

May 5, 2026

} I am submitting an update to my previous complaint. In my original complaint, I stated that the vehicle had not received transmission service. After reviewing my records, I confirmed that a transmission fluid service (drain and refill with inspection) was performed at an Acura dealership in July 2024. Despite this maintenance, the transmission still failed at approximately 84,000 miles. I am providing this update to ensure the complaint is accurate

NHTSA ID

11733622

Incident

Apr 23, 2026

I am reporting a transmission failure in my 2021 Acura TLX with approximately 84,300miles. While driving under normal conditions, after about 30 minutes on the road, I came to a stop at a red light. When I attempted to accelerate again, the vehicle would not shift out of first gear. The engine would rev, but the transmission failed to upshift. I also experienced a hard and abrupt engagement when shifting the vehicle into reverse. This issue occurred suddenly without warning and made the vehicle unsafe to operate in traffic, as I was unable to accelerate properly or maintain normal driving speed. The vehicle has been regularly serviced at an Acura dealership. At the time of the incident, the transmission fluid had not yet been replaced but had recently been recommended during a scheduled service visit. The vehicle is currently at an Acura dealership where I normally get the car serviced. The dealership has diagnosed the issue as an internal transmission failure and is recommending a transmission replacement.

NHTSA ID

11733596

Incident

Apr 23, 2026

2021 Acura TLX A-Spec SH-AWD and my transmission is leaking from the seal between the transmission and the differential. Acura is not sure if they can cover it under warranty because I am slightly past the powertrain warranty even though they had my car about a week ago when it was just barely past that point and no one said anything about the leak on the transmission until I checked with a certified Acura mechanic somewhere else.This is not just some small problem because with fluid leaking and leaving it will eventually damage the transmission and the differential or even just make them completely give out. This can be gears grinding and overheating. It is not just a problem it is also a SAFETY HAZARD if this starts dripping onto the exhaust pipe or even on the road behind making traction a problem for someone behind. This needs to be under a recall not just warranty with how much I see this happening to these cars this is ridiculous we have to go through this.

NHTSA ID

11731669

Incident

Apr 2, 2026

Transfer Case has gone out. No longer getting power to the rear wheels as it is a AWD car. Problem has not been checked by the dealer yet. There were no warning lights on the dashboard when it went out.

NHTSA ID

11729499

Incident

Aug 21, 2025

The all wheel drive failed do to transfer case splines being sheered off between the transmission and transfer case. No warning lights are on to warn of the rear wheel tires not receiving power to them. I was not aware of this problem and this could have contributed to and accident, as I though the AWD was working, but it wasn't.

NHTSA ID

11725554

Incident

Aug 1, 2025

Transfer case needs replacing

NHTSA ID

11725109

Incident

Dec 15, 2025

My vehicle was performing as expected, but there was a smell of burning oil or rubber. When I took the car into the dealership the found that the transmission was slipping and the transfer box was failing. In the video they sent of the initial inspection there is obvious brown sludge leaking from the transmission. I was told that a complete transmission and transfer case was required.

NHTSA ID

11724400

Incident

Mar 13, 2026

Driving towards the gas station, still at lows speeds while I was in the neighborhood so speed limit was 15mph. I can hear and feel the car struggle to move forward, about 2 minutes into the drive a hear a big TOON and check engine light is on for about a minute before going away. I filled gas and headed back home and I heard a larger TOON but this time all the warning light came up. These are all errors reported by the car at the same time - Vehicle Stability System - Hill Start Assist Problem - Addictive Cruise Control System Problem - Collision Mitigation Braking System Problem - Road Departure Mitigation System Problem - Emission System Problem - All Wheel Drive System Problem - Brake System Problem These are all errors that appeared on the Acura app - Emission System Problem - Vehicle Stability System - Electric Parking Brake Problem - Electric Power Steering Problem - Adaptive Cruise Control Problem

NHTSA ID

11723440

Incident

Mar 1, 2026