Face it. Your transmission is dead. It's the most expensive part of a car to rebuild.
Yep. If I were a GM dealer I might say the same thing - just to extend the time frame so that it could no longer be considered covered by any manufacturer's warranty. They "couldn't find a problem" because they didn't want to, and your A/T wasn't quite dead yet. So they stalled you to buy time. Time passed. Now you no longer have an actionable complaint.The fluid level is fine. It was inspected by two different GM dealers prior to the train warranty expiration and they said they couldn't find a problem. At that time it was having trouble shifting above 60mph, which is still a problem.
It's like taking candy from a baby...