cv and diff
 

I have a 02 4x4 ls.
Just had to replace my crank shaft sensor. As i was under it i noticed the passenger cv axle had side to side movement from the diff. Is that normal?
If not what could be causing this? The cv axle is a month or 2 old. Could my diff be shot iv been chasing this noise. Its like a thump something that is with the speed. No matter in4x4 or coasting or reverse. Any help would be awesome.

I have that happen some times but dont know what it is and havnt really tried finding whats causing it