I have a 2008 Crew, 4.8, 3.23 gear/ locking dif. AT. When I'm just rolling to a stop and sometimes come to a complete stop, I hear a sound in the rear end that sounds and feels just like having a 1 7/8" ball with a 2" tongue. It just has started and since I bought it in Oct. 2008 I don't have long before the warranty is out! I've just pulled a motorcycle trailer with it twice since I had it. Is this a common problem? Thanks in advance.