That's no problem at all. We all make mistakes.
P1744 Torque Converter Clutch System Stuck in Off Position.
I would still check the tranny fluid like I described above (if you need more detail in how to do that, just ask), but unless its just an electrical problem it sounds like your mechanic might be correct.
If you want to go through the extra work (and you will when you find out the cost of replacing the torque converter) you could search the Transmission forum for that code. Chances are someone else has encountered this and there's advice on how to deal with it. Maybe its a simple fix that won't involve major work on your tranny.
