6 months after I took my new Sonata home, it was down-shifting from second to first really hard. It was jerking myself and my kids forward when we took the corner before we got to our house. I brought it in to the dealership and they said they didn't feel a problem (bullshit). They did offer to reset the system and see if it would fix the problem. It did immediately. Now months later...it's a issue again. I'm so over it! Just over a year old and it's been back to the shop too many times. Not to mention at 3 months old it was in the shop for a week because some computer component died and I had to manually put it in gear to get to the dealership without working lights, blinkers (yes, I use them), horn, working windows, locks, couldn't even open the trunk... NOTHING! I'm ready to give it back!

On September 201. Dealer (per instructions from Hyundai Tech Support) replaced the transmission. Dealer contacted us (after 1 day) and informed the transmission had been replaced and the hard shifting was no longer present. We took the car home and drove/test drove a few days. We concluded the same problem/issue was still present and notified the dealer.

Service tech test drove the car and informed us that he believed it was not a mechanical problem, but a 'software' issue, that had not been address by Hyundai yet. Service tech had us test drive a new comparable 2018 Sonata to see if the problem with the hard shifting was present, but we could not get the problem to replicate in the new Sonata.

Service tech told us the reason the transmission was changed it was because Hyundai felt that since they did not have a know problem on the books, it was best to replace the transmission and see if that corrected the issue. July 2018: We returned the car to dealer and dealer kept the car overnight to evaluate the problem and contact Tech Support Again.

Today September 13 dealer notified us that Tech Support had them 'reset' all the values of the transmission programing (software issue). We test drove the car, it seems the problem/issue has been resolved for now. However, we did notice a slight 'clicking noise' when downshifting occurs. It does seem that it was not a mechanical problem, rather a software problem.

Purchased new 2018 Sonata SEL in California. After several months had passed, while driving, the transmission starts to hard downshift when the brake is applied and released. The problem occurs when the driving mode is on ECO and COMFORT, and also in the SPORT mode. The hard downshift occurs only when coming to a stop at speeds between 10 to 15MPH. It looks like after the brake pedal has been gently applied and lightly released but my car itself applied its brake again briefly. It seems this is a programing issue related to the transmission (bad software?)

Purchased new 2018 Sonata from Bert Odgen Hyundai in Harlingen TX in Aug 2017. A while back, while driving, the transmission starts to hard downshift when the brake is applied. Car taken to dealership and service tech said, more than likely they will replace the transmission (once the manufacture approves it). Last week, my wife and I tried to pinpoint the problem with the transmission and found out that this hard downshifting and jolting/thumping of engine and transmission only occurs when the driving mode is on ECO and COMFORT, but not in the SPORT mode. The hard downshift occurs only when coming to a stop at speeds between 11 to 14 MPH and after the brake pedal has been gently applied and lightly released and they applied again (this is a normal driving condition when most of us are coming to a stop). It seems this is a programing issue related to the MPG!

Update from Jul 6, 2018: Updated June 2018. Dealer (per instructions from Hyundai Tech Support) replaced the transmission. Dealer contacted us (after 1 day) and informed the transmission had been replaced and the hard shifting was no longer present. We took the car home and drove/test drove a few days. We concluded the same problem/issue was still present and notified the dealer. Service tech test drove the car and informed us that he believed it was not a mechanical problem, but a 'software' issue, that had not been address by Hyundai yet. Service tech had us test drive a new comparable 2018 Sonata to see if the problem with the hard shifting was present, but we could not get the problem to replicate in the new Sonata. Service tech told us the reason the transmission was changed it was because Hyundai felt that since they did not have a know problem on the books, it was best to replace the transmission and see if that corrected the issue. July 2018: We returned the car to dealer and dealer kept the car overnight to evaluate the problem and contact Tech Support Again. Today-July 6 2018, dealer notified us that Tech Support had them 'reset' all the values of the transmission programing (software issue). We test drove the car, it seems the problem/issue has been resolved for now. However, we did notice a slight 'clicking noise' when downshifting occurs. It does seem that it was not a mechanical problem, rather a software problem.