I started hearing a harmonic noise coming from what sound like the drivers side front end of my 2015 HSE with 42,000 miles on it. I thought it was a CV joint or possibly a wheel bearing but when I took it to our local RR dealer they said it needed the front differential replaced. I picked up the RR a couple of days ago and the noise appears to be "mostly" gone. I say "mostly" because I still hear a slight harmonic sound (increases and decreases with acceleration/de-acceleration) coming from the front end. I intend to take the RR back to the dealer but wanted to get a bit better educated before I do. I have a few questions: Is is normal for the differential to fail at 42,000 miles? What can cause a differential to fail? Could a failed differential cause other issues (i.e. premature wear of CV joints, drive shaft, etc)? Thanks in advance for any insight you may be able to provide.