So something very strange happened on my trip this past weekend. I have a 2001 U320, I did my preflight checks of pressure and fluids before leaving (all normal).... about 2hrs into my journey I saw a splatter via rear camera on my enclosed trailer front. I didn't know what it was, but upon my rest stop I was very evident that it was oil! The backend of the drivers side was where everything was wet most, (the Haladex) lost about 3+ quarts of oil, BUT with the engine running I found NO leak. I cleaned the very messy Eng bay, and Eng door, I looked for loose hoses.... Nothing found. During my driving I have a Road Relay 2 that monitors everything. Oil pressure was solid at 33-37. All temps and other pressures normal. The 400 mile trip home was uneventful and after post flight checks..... oil level is perfect and where it was for the return trip home. Baffled to say the least. Like it had an embolism. Hoping to hear from anyone that has had something similar or might have a clue as to what and why. Now to de-grease everything.
And, you are sure it was engine oil (black), not diesel (different smell), transmission fluid (pink) or hydraulic system oil (clear oil)?
Check your air filter. I had a similar oil loss on my return trip from dusty Alaska. Didn't see any oil on my toad but had lost a couple quarts. Air filter was clogged, changed it and no other problems.
As Brett it could be anything. Check your hydraulic fluid and trans levels.
It's definitely not the hydraulic oil for the fan/steering.... that's clean. It was definitely oil, black and made a mess. The air filter is 4K miles old. It's a mystery. I'll keep looking and maybe more ideas will pop up.