Front end knock

OK, since the first day i bought my truck, there has been a knock when going over bumpy roads. the road i live on is terrible so i hear it every day. Its not overly noticable but its always there. Because it was new i thought i could rule out sway bar bushings, although it does seem more prevalent in colder weather which would make you think bushing. I dont think its it though. What i noticed on my truck is the front drive shaft, on both sides, fits loosely in the wheel bearings. I think that may cause the knock i hear.

Anybody have a similar issue or other ideas to look for?