2021 Kia Forte

The transmission went out while driving, entering the highway. It was intermittently missing a gear or slipping in about 2nd or 3rd gear. I first noticed it going about 40 mph and trying to accelerate to highway speeds. It was during a winter storm and other vehicles behind me had to brake unexpectedly. I wasn't sure if I felt for sure, so I continued to drive through many inclines and declines. The inclines became more difficult and the inability to maintain consistent speeds. I drove gently to the nearest Kia dealership which was in Salt Lake City about 60 miles away, where they informed me that I needed a new transmission. The car had about 75,000 miles on it and I bought it as a certified Pre-owned Kia with about 4,000 miles on it. The dealership plugged in the diagnostic code reader. But there were no codes detected. The service tech drove the car and felt the issue. A warranty representative inspected it about a week later. There were no warning lamps while I drove (mostly coasting downhill) from Rock Springs, WY. When I arrived to Salt Lake City, the triangle warning light came on. I drove about 10 more miles and the engine light came on. Almost all mileage has been on highways and at highways speeds as I commuted 75 miles each way for work on a turnpike between eastern Oklahoma and Fayetteville, Arkansas. There was little city driving. I lived in a small town. So, I had to travel state highways for most all errands (groceries, medical, etc.). There were no mechanical issues with the car ever until this.

The issue I’m having was confirmed by the dealership so when I drive on the highway, there’s a specific patch of highway that zigzags the car will follow that zigzag after getting off of the highway onto regular road. The car computer system will start a down shift erratically and feel like the car is pulling backwards. Also there is a lack of acceleration and it feels like the transmission is slipping, but I have confirmed with the dealership that the transmission was not slipping that the computer was shifting erratically. They would reset the computer and the car would would begin driving in a more normal state shifting correctly. I get on the highway again. The car once again will start shifting erratic. When you let go of the gas, the car downshift so many times that the car almost comes to a complete stop without hitting the brakes. The dealership has the car once again trying to figure out what’s going on with the car and why when I go on the highway the computer starts shifting erratically on that specific patch of highway. The car will pull left and right the entire time once you get off the highway the erratic shifting happens the dealership let me borrow a car which is a 2025 Kia Sorrento went on the highway with the car and had the same exact issue. The car they let me borrow is also downshifting erratically and feels like the transmission is slipping. The dealership did confirm that the car was not driving as intended, and they were confused as to why it was happening. They’ve also confirmed that the test that they’ve done on the car itself. had not passed prior to them resetting the computer.

It seems the car may have a defect in the transmission(Dual Clutch). The car makes at times an abrupt stop, for like a second or two, after I press on the gas. When I'm driving, especially at low speeds I can hear the transmission's parts make a grinding sounds, loud clicks. When I'm breaking, it's not smooth at all; I feel the car pulling a bit when switching to lower gears during the breaking process. When I have the car on and not moving (i.e parked), I can hear sounds emanating from the bottom of the car, like parts grinding against other parts. I have not seen any indicator light turn on from the vehicle, to this day. I have taken it to the dealership before, more than once, but they haven't found any issues with it. Still I feel they have not done a full inspection of the car, and I feel something is off with the transmission, like there's something loose somewhere in the car.

The contact owns a 2021 Kia Forte. The contact stated while driving 70 MPH, the vehicle started to decelerate while the RPM increased. The contact pulled over to the side and notice the vehicle smoking but there was no fire. There were no warning lights illuminated. The contact towed the vehicle to a local dealer, where it was diagnosed and determined that the transmission needed to be replaced. The vehicle was repaired however, the failure persisted. The manufacturer was informed of the failure. The failure mileage was 35,642.

Vehicle has issues where transmission actuator will stop functioning causing sudden loss of acceleration. Was doing 70 MPH in expressway and vehicle stopped accelerating. Issue has occurred two times, both times being serviced by Dealership, after receiving the vehicle back, issue still persists, vehicle lost acceleration suddenly when turning into a intersection.