Rear differential fluid leak

[Bobby_Drake]

So rear differential on my '16 X5M was noted to have a leak by my indy shop during oil change. I'm barely at 22k mi. Anyone with rear differential issues or leaks? Fortunately, I'm still under warranty so I brought it to the dealer and they replaced the rear differential. SA told me it was a $5K job inclusive of parts/labor/taxes.

Never got a straight answer why it happened. But it made me think; when do you change the rear diff fluid? Also, how common are these issues?

[DgjoX6M2016]

They changed my rear diff fluid last week at 40k miles.

I had a xfer case leak that required replacement of xfer case. 35k mikes.

[Bobby_Drake]

Were you under warranty?

[DgjoX6M2016]

Yes. All under warranty. Got mine CPO so good for unlimited miles and end of 2020.