Absolutely racking my brain trying to figure this one out. When I'm driving the jeep around in 2wd, any bump I hit makes a loud clank sound from the front end. The only noticeable play I can feel is rotation in the front driveshaft, but from what I understand, thats normal to an extent. If I rotate the driveshaft by hand quickly, it sort of mimics the sound I hear when the shaft reaches the limit it can turn. Can't see any play in the shaft u joints at all when this is happening.

But when I take the jeep out and put it in 4 wheel, the sound goes away. You guys have any idea what this could be, so I can get an idea where to start?

 

Hit a bump & it rattles......check the upper shock mount.

 

Shock mounts good, it only happens in 2wd and nothing else which is why im confused by iy