Noticed a leak on differential

2006 Nissan Frontier 28500mi. Noticed an old leak around the upper bolts on my differential. No dripping and the old oil leak is somewhat covered in dirt. Makes me think it happened a while ago. I’m going to take it to the dealer (still under warranty) to check it out. Is this a normal thing from the factory?? I don’t have any noise from the rear while driving - yet… What would cause that leak? Thanks.

there is a vent on the top of the diff. it may just be from that. oil leaks on diffs. usually occur on the bottom of the diff. thats where most of the oil is. clean it off with a pressure washere and swist the vent in a circular motion to make sure its clear. most rear wheel drive vehicles will have these spots of dirt and oil residue on them.

This “misting” probably doesn’t qualify as a leak.You might get a diff. service out of it.Probably wont be a issue after car is out of warranty.