One problem related to transmission noise has been reported for the 2012 Kia Motor Optima. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 Kia Motor Optima based on all problems reported for the 2012 Optima.
Transmission issues: between 2nd and 3rd gear. Would lag then jerk the car with some torque once it caught 3rd gear. Had to get 2 replacement transmissions because of this issue. Also engine seizer issue, my engine started to seize when I was going 45 miles an hour with alot of traffic behind me. Then all of a sudden it started making loud thunking noices then a very loud grinding noise and then I was stuck on a road not being able to get above 22 miles and hour, there was no shoulder to pull over. And I was stuck trying to go uphill and all these cars behind me. I ended up having to stop the car and leave it in the middle of a 2 lane road on a hill with the emergancy break on. Kia knew it was another seized engine which I thought it was my transmission again which I had brought in because this 3rd transmission was having the skilling issues around 20-25miles and hour, but after they knew I wasnt going to buy another kia again they wouldnt fix my trans that should probably be recalled anyways. But they thought it was another Optima seized engine, and even though all Optimas are recalled for this exact same issue, they say that mine isnt covered becasue its a hybrid and has a motor in the car also so its different set up. But theres are others online with this kia Optima 2011-2013 hybrid engine seizer just like all the other Optimas. And I think the hybrids should be included in the recall. As we are having the same issues. This was a very dangerous issue.