2021 Acura TLX Transmission Problems

Mileage when the problem started

Owner reports

Selected complaints filed with NHTSA by 2021 Acura TLX owners, lightly cleaned up (personal details are redacted by NHTSA).

I drive a 2021 Acura TLX 2.0 L turbo 4 cylinder. I was driving to work on [redacted] 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. …

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. …

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. …

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. …

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. …

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. …

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 …

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)

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

My car has suffered a well known issue in the 21-25 Acura TLX community. At 71,000 miles my transfer case splines stripped also with the transmission splines. Resulting in me having to pay out of pocket to replace both the transmission and transfer case. I'm really hoping Acura does a recall for this issue. I really like this car and don't want to have to replace them again. Like I mentioned before. I'm in a Facebook tlx group and people are constantly posting about theirs blowing.

NHTSA investigations

Transmission complaints in other TLX years