2000 Toyota Tacoma P0770

I have a 2000 Toyota Tacoma and my check engine light came on. Had the dealer check it and they said it was the P0770 code which means my Torque converter is not locking properly and suggested I replace the transmission. Can this be correct? I am driving it and I have had no problems with the transmission shifting properly. Everything seems to be fine. I had the transmission serviced 10000 miles ago. The check engine light is off now but can I still drive it? Should I have the transimission flushed again and see if it helps? Any help will be appriciated.