I have a IX MR with ~9500 miles with just slight mods -- TBE and tune (and increased boost). I have noticed that there is a black oil film on my differential (right behind the oil pan), but no spots on the garage floor. My engine oil seems to be fine, although if this were a super small leak I may not notice as I change my oil every 3 - 4K miles. Any idea where this oil could be coming from and is this a common problem? Thanks in advance.

 

AM bump....Anyone else seeing this?

 

afternoon bump...

 

Clean off the spot really good with brake cleaner. At the next oil change see if its still there, it may be stray oil marks. Also if it returns there may be a small leak that only comes up as you drive and the movement of the car and wind blows the oil the that location.

 

I just fixed a similar problem on my 03 VIII. There wasn't enough to drip on the ground but the back of the motor was wet. Ended up replacing my headgasket, as it was leaking from the back side.