Don't worry too much about the motor or tranny. You can't over-rev a diesel as they have govenours (spelling?) on them. Who knows what they did to the transmission, but as long as it runs fine now, maybe just go get the fuid changed to make yourself feel that you've done all you can, and hope for the best. The steering is probably crooked because the drove over a curb and bent a tie rod or just knocked it out of alignment. Take it to the dealer, tell them what happened, and have them check it out.