I'll make it short and brief:

I have 72k miles on the car, dealer replaced the tranny at 59k for the same error code. A year later, the same error code comes up, and now I'm clearly out of warranty. Dealer wants 13 grand for a new transmission.

Car's driving perfectly fine, but the error light stays on. What do you guys think I should do?

Keep driving it if its not feeling different or get a rebuild for ~2k and have peace of mind.