This goes on, after a lot of messing with a front drive shaft I think my front diff is faulty, when I drive forward it seems to lock up but not in reverse, when I turn the shaft by hand it seems to rattle near the diff so I've removed the drive shaft and when I run the engine it rattles that side in...

The passenger side wheel bearing went so I replaced it, then the UV joint went on the same side almost straight away, I fitted a new one and it seems the shaft will not lock.in to the diff, it just slides in and out, any ideas please