I recently had the diff covers off on the 2011 and repainted them, after I cleaned up the rear 11.5 I noticed stamped into the cover the words "fluid level" with a double line, this was a good inch below the bottom of the fill hole, just a heads up to not over fill. There was no such mark on the front cover so the "standard" 1/2 inch below. If I hadn't cleaned them up with lacquer thinner before paint I would never have seen the mark.

 

Never did understand why AAM did that. If it's a real issue why didn't they just relocate the fill plug an inch lower? I'm only guessing as AAM didn't want fluid leaking from the fill plug (customers complaining).

I fill to the plug level and call it a day.