is my transmission blown?

Have you checked the transmission fluid level?

Yes, we actually took some out because it was over the fill line.

It is definitely your auto trans. It could be something simple like a shifter cable or valve in your trans to a clutch multi-disc, valve body, stall speed converter ,or a rebuild job. Most trans shops just replace the whole trans. Your options are enact the "lemon law" or get the "as is" truck fixed. & expect to pay big bucks, the worst case scenario.Shop around for your best trans price.

could be a few things besides trans gone like jimz said main thing since u know nothing @ autos find a reliable trans shop ask freinds ,coworkers anybody you know&trust this could b fairly cheap or expensive.

I think it's your tranny, better get it checked out and don't listen to jackweeds on here! They don't know there ass from thier elbow, I know your skeptical but get a checkup from the neckup