I have a2013 tahoe Transmission went out so I swapped it out with a used transmission 6l80 out of a 2013 silverado. It has been running fine however if you go over say 40-60 miles an hour and then stop a few seconds later it feels like somone has rear ended you. Any ideas as to what is causing this. Does it need reprogramming or a relearning program hooked up to it or flashed. I am stuck