Right front Axle shaft making noise.

OK so i thought that i had a ball joint going out and had already ordered those :fustrate: ... So i got under the truck and looked around and the u joint where the front shaft connects for the lock out, (guessing thats just called front axle shaft) was wobbling around and making all kinds of noise. I have recently replaced front wheel bearings and seals in the front hub. So why would this shaft and u joint just be rattling around?

Here is a picture of the shaft and wheel bearing and hub.

I dont really want to replace that seal again but will do it if needed, could something that the shaft connects into insde the differential thats worn out?

CORRECTION : Left Front, Drivers Side

Anyone ? Thanks for looking