Card in spokes noise when I go over bump
 

Occasionally, not everytime my truck makes a sound that reminds me of a baseball card in the spokes of a bike. It usually happens when I go over a bump but sometimes it just happens as well. Like I said it is not a constant sound, very random and does not last long. Also, it is not a loud noise but noticeable. Any ideas on what it could be?

Have you used a creeper to check out the entire underside of the vehicle? Could be something is coming loose or broken, or there is some kind of debris under there. Where is the sound coming from exactly?