I work in a body shop and I had a late model Ford Windstar come in late Friday because it rolled into a house. So the lady claims the van was running in park and that it slipped out of park driving itself into the house. She is also now compaining of it clunking really bad when you shift in into gear and other stuff. I dont know a whole lot about how a transmission works and is it possible that van really slipped out of park? How could this even happen? I need some ideas so I do not look like an ass when I have to tell my boss what I think is wrong with the transmission.