Nissan circlip 382258S11A
Only way to rule out damage inside the front diff is to drop it and open up the cover; inspect the pinion gears/teeth as what Nissanlover had to do. Also, anytime the cv flange continues to pop out of place, its a sign the circlip has worn down. With the front diff out, I'd replace the (2) cv flange seals and rear main seal since it easier with the diff out of the subframe.
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