2012 super duty rear diff fluid gray

[amailloux]

Is it normal for the rear diff fluid from the factory to be dark gray. I took a sample from a 9000 mile truck and have never seen fluid this dark gray. seems to be suspended but after setting for 12 hours it hasn't collected at the bottom. i found no ssm's or tsb's for super duty rear fluid. I can get a picture if anyone really wants one.

[Brad Clayton]

There is a message out there somewhere about gear marking compound used at the assembly plant causing discoloration.