Bump-bump! Where's my transmission?

I recently crossed a railroad track and suddenly my transmission wasn’t speaking to my engine. The engine ran fine, but it was as if my transmission had disappeared. I had it towed to a dealer who replaced the fluid and torque converter. My main concern is that the same dealer had serviced it a week earlier for a “check-engine” problem, and replaced an electric sensor. So my first impression was that the bump of the tracks had jarred something loose. Otherwise, why would the problem appear so suddenly?

Coincidences do happen.

““check-engine” problem, and replaced an electric sensor” is way too vague for anyone to say anything about it. You’d need to post the exact error code(s) that were read from the computer and what the name of the sensor was. You might check you invoice for that info.

Either way its fairly unlikely to have anything to do with a torque converter failure. I’m not sure why a trip over railroad tracks would lead to the sudden death of a converter, but with the minimal infomation you’ve provided there’s not much that can be said except that coincidences do happen.