Leaking front output transfer case

[Tyy1907]

Truck has all of 15000 kms so still young

I noticed the seal and boot beside it looked wet or more accurately, was wet at one time from oil.  Pulled the fill plug and stuck a tie wrap down and its maybe 3/4" below.  And that's in my sloped driveway so its maybe 1" below when level.  

 

The manual says only to add oil when its below the drain plug, which seems odd.  Should I take it in?