LT1GMC

How many C7 Differential issues have occurred on under 50 k cars that had never had the rear lube changed? Reason I ask is I've seen several videos of differential lube changes on lower mileage cars which the lube was grimy dirty with quite a collection on the magnets. That was how mine was at 40K miles. Never have I seen that dirty or dark lube even on my Yukon's changed for the first time at 120K miles. Wondering if that is a contributor to differential failures and if it is a one time first change dirtyness or after the second change as well. And maybe related to the electronic differential since it may allow more slip and more often than the older locked up all the time until forced unlocked on a turn differentials, meaning more wear particles.
Could be more regular rear lube changes may be in order?

AnotherNorskie

It certainly wouldn't hurt. I have 81k on my C7 and have no service records that it was done before I did it at 75k. What came out looked like molten lead (I like to call it unicorn blood). But my non-electronic diff is fine (so far).

On other cars I've been doing diff fluid changes about every 50k and it was never that silvery.

The early diff failures might be related to factory underfill of the diff.

Random Dan

So I did a flush. It was not low but the plugs were certainly only just barely tight enough to stop a drip. It was wicking out. Magnets were covered in metal. Might be looking at a wavetrac soon. 56,000 when I changed the fluid.