The automatic transmission on the vehicle failed without warning. Vehicle was driven on the highway without issues; exited highway to a city street, stopped at a stop light, and turned onto another street. Upon turn onto another street, transmission did not upshift as it should; it was noticed the engine was revving high, but transmission did not shift. Tried to manually shift, with no luck. There were no warning lights or messages present at any time. Vehicle was stopped in a safe area and turned off, restarted, and tried again. Transmission still would not shift correctly; when it tried to shift, it would clunk, and it sounded like something dragging under the vehicle. Drove vehicle home and parked it. Later when transmission was shifted into gear, it did not move, and made a terrible clunking noise, then a squealing sound. Called dealer and had vehicle towed in for inspection. After inspection, manufacturer replaced failed transmission under warranty. Per dealer rep, transmission failed, and registered two internal codes, one for incorrect gear ratio, and other for torque converter issue. While the codes registered internal, unfortunately there were no warnings issued to driver. Safety was put at risk because if the failure happened while on the highway three miles earlier, there was no warning to driver who was driving in heavy traffic, and they may have been involved in an accident. The only reason the driver was aware of the issue was because they could hear the engine revving high, and they pulled over to inspect. A less experienced driver may not notice the same issues. Additionally, it's concerning that transmission codes were stored internally but did not trip any transmission issues or loss of power warning; this could prevent drivers from noticing issues prior to failure. Lastly, the vehicle health report we received from Acura on 12/31 (and states as of 12/12, day after failure), stated there are no transmission issues present.

- Appleton, WI, USA