Oily residue on rear axle / transfer case. Cause for worry?

[940RHO]

Hey all. I was actually looking at the muffler section to see if I wanted to go and chop it off at the muffler shop over the next few days and notice near the transfer case and rear axle on the passenger side. If you will there is an oily residue covering a portion of the assembly. It is not dripping, but when I took a paper towel to it, it did have a good amount of dark residue coming off of this area. It’s isolated to the passenger side.

Is this cost for concern? Could this possibly be the lubricant used for assembly working its way out?

I’m at 8700 miles on the truck since April for context.

 

[RHOfan]

I’d have it checked by my dealer. Doesn’t look right, unless something got spilled on it, to your knowledge.