I wasn't sure where to post this, as I haven't figured out what is making the noise. The truck moves and drives without any noticeable problems, but when I place it in reverse, I almost always hear an audible "click" after moving about 5-7 feet backwards.

I realize it's a pretty vague description, but does anyone have the slightest clue what this could be?

2002 F-150 SuperCrew
4.6L 4x4 w/ just 50k miles.

 

First thing to check would probably be u-joints. It could also be a parking brake issue. Guessing here, but it might be an issue with the 4wd actuators.