Just replaced the front diff on one of the Z550EXs, two of the bolt on the crown wheel came out and shattered the front right of the diff'.
Lucy we have a crashed on that is being slowly robbed, (aka Awaiting parts).
So if you hear anything like a clicking from a diff, front or rear, check. after  popping out the drive shaft and removing the three mounting bolts you can just about wiggle it up enough to undo the side cover bolts and have a look

[2015 Z Force 800 53/Trail EPS]

Good to know. Thank you. More loose bolts...