The engine didn't quit,it made a loud noise in the rear end of the car, then he pulled over. The engine runs and starts fine. When he got it back from the machanic it acted the same way it did before he took it to him ( pulling and not picking up speed, but without the noise). Now the car will not shift out of first gear(automatic transmission) and the machanic is saying it is in the transmission. There was no indications of transmission problems before. Please explain how the rear end works with the transmission and what I can tell him to tell the machanic.