Ratter, on a stock car, assuming the chain guide hasn't jumped, no overheating, no constantly hitting the limiter, etc. What are the chances of this happening, ie. a normal car, nothing wrong, just your standard services? I'm guessing the chance is close to 0 without some other contributing factor. In that case, I'd be putting this to Ford, get them to explain how it could happen to a car where the chain hadn't jumped. Also, ratter how come the chain jumps? It sounds like it's more common than I first thought?