I've been down the lemon law road and it is a pain. I went to arbitration with GM over a Z06 with a grinding transmission. I didn't use a lawyer just the BBB. Check your states lemon law. Each state is different with different time and mileage requirements. One other thing to check, a Lemon Law is state specific. For instance in Indiana, you must purchase the vehicle, title the vehicle and live in the state to be covered by the Lemon Law. I found this out the hard way with a CTS-V, purchased it in Kentucky so had to do the Magnuson and Moss act route. Make sure you follow the rules outlined in the owners manual with notification to GM, make sure it is a certified copy with receipt requested. I had that little game played trying to not cover the full cost of the buy back. Take good notes with the dealership, how many days out of service, who you talked to on what date and what was said.
It is a pain but in the end you can win, make sure the SAFETY factor is stressed. " I travel on a heavily used road with many 18 wheelers and if the transmission were to fail again, I would be concerned with mine and my family's safety."
Good luck.