I have read that symptom in here that if there is nothing wrong with the actual TCM and the tranny itself, you can disconnect the battery, wait 30 mins, reinstall it and that should reset it. what you are experiencing is what they call "Crawl mode" or something. Sometimes, when it is cold, mine would do that too, but i let go of the accelerator and it shifts. sometimes, i shift it back to neutral and then shift it to drive. that seems to work. Hope it helps. that's just based on what i've experienced so far.