AFAIK, there isn't any single "main" code that these transmissions set for hard shifting. If you don't know the code(s), it's better to say that than to give them one that you think it was, as that could lead them in the wrong direction. Frankly, if they are going to do a full rebuild, and do it well, I don't know why they would want to know any code(s) or even any symptoms of what it was doing.
Note that "1703" is not a valid OBDII code. There is always a letter preceding the four numeric digits. P1703 would be a powertrain/emission code. In this case, it is Brake Switch out of Self-Test range. It's what you get when you initiate the KOER (Key On Engine Running) self test and then don't press the brake pedal at the correct time. B1703 is a body code, and it would be Seat Driver Recline Forward Switch Circuit Short to Battery. There are other beginning letters that it could be, but I don't see running though all of them.
