Vehicle Shudder problems of the 2011 Audi S4

I was cruising at approx. 55mph on my way to work. I had no symptoms of anything prior to the transmission failure. Suddenly the car started vibrating and decelerating as if I had a flat tire. I made an emergency merge into the center median and was luckily nobody rear ended me. After inspection of my tires which were ok I got back in car. D or r would not work. The car would not move.