what would cause the transmission to quit, wont go into any gear, towed home on 1999 Oldsmobile Aurora

the trans fluid was changed along with the filted, still nothing it's like there is no transmission

Asked by for the 1999 Oldsmobile Aurora
was the ck eng light on b4 this happened, scan codes and post but as prof g says its to little to late
1 more answer
The transmission is probably bad; If you have high mileage, and have not had it serviced, it's a little to late to service it now. Was it slipping some before this happened. Might try some place like AAmco for a free estimate.