I don't see how they can say it's not a power-train issue. It's the freaking transmission!
The only reason why there would be a recall is if it happened to a lot of people.
They are jerking you around.
Tell them it's a transmission issue, therefore it's power-train and if they don't want to fix it you'll be back with your lawyer.
Or my personal favorite is to go in there with a bunch of flyer's printed up stating "They refused to honor my warranty and because of that I am driving an unsafe car."
If they ask what the flyer's are for, tell them you are going to hand them out on the Sidewalk to everyone that walks by or comes in.
They will fix it

.