What could cause my car to stop moving though in drive and the speed meter moves

Take to transmission shop for diagnosis....

My 2008 Suzuki xl7 transmission kicks back. When ever I am on a free way driving straight forward it drives correctly, but when i am driving local streets or slow down or stop in a a traffic, the car transmission kicks back and I can hear a heavy noise coming from the back of the car like a metal that hits another one heavily. Also, the transmission is slipping when slow down or stop for a traffic. What can create these problems? What should I do?