I bought a 2010 Civic EX with 89k back in Feb. It didn't shift into 5th right away one night when it super cold, it smelled overheated but it eventually shifted and I made it home fine. Gave me the same problem the next morning. Took it into the Honda dealer that same day and they said the transmission fluid was low and dirty. They drained and filled it a few times and that seemed to solve it. It randomly downshifted one morning so I took it to a transmission specialist and he let it sit overnight. Found no leaks but he did say it appears as though the Honda dealer didn't fill it all the way, so he topped it off. I took it back to the Honda dealer to tell them they hadn't filled it up right and they reset the transmission computer for free. This way it would re-learn my driving characteristics and start hopefully shifting smoother. Now, at 99K, the transmission has been doing just fine since, but I still notice when it shifts into the final gear it shifts a little hard but that's only when I leave for work and after that it drives fine once its warmed up good. It doesn't do this all the time, but it always shifts into gear. I am worried the transmission got damaged when I overheated it. Sometimes it doesn't have a lot of power though. It sometimes downshifts late when going up hill. I've been checking the fluid on a weekly basis since and it appears full and clean. I have no clue what the previous 2 owners did but the last owner didn't have it very long. They had to be pretty careless people. Could this be a bad shift solenoid or maybe even a bad torque converter? There are no lights on the dash and it never threw any trouble codes. This car has been a big mystery but it still runs like a Honda. Thank You.