A couple of issues here. On the way home I thought I ran over a twig or rock which was rolling around the engine, apparently the serpentine belt fell off. I checked around the pullies and found that the spring tensioner easily moved up and down. My question is, should I replace both tensioner and shock as well as the belt? What would be the best way to do that? Lastly, does anyone have a picture of the pattern that the serpentine belt winds around the pullies?

Thanks
Mitchell