My ear is okay. I started working on it about 10 years ago when I got my first church job. I started playing piano seriously when I was about 10. From age 10-17, I studied mostly classical. But due to my job playing for a youth choir, I had to play gospel. They supplied the sheet music, but it was not always available. I could always hear the bass line and I could hear the melody line, but I had to figure out what was in the middle. Sheet music helped, but usually only the first time around was transcribed. Due to my classical training, I was very meticulous in getting the right notes. So I spent many nights up late trying to learn a song for the next morning at church.
At first it was like this: listen to 3 seconds, try to hum or process in my head what I just heard, then translate it to the piano...or rewind (back in the days of cassettes) and listen to it again. Now depending on the song and how full the instrumentation is, I can usually pick out what is being played rather quickly.
If anyone has seen a couple of my youtube clips, you'll know that I try to play exactly what is played on the original track.
(mike bereal played the original)
(Cedric Thompson on the original)
(Kevin Bond on the original)