Looks like the axle stub shaft seal is toast. I would guess its a standard seal, so you can get the dimensions from the seal itself, and order a replacement. Don't let the oil run low.
I am not familiar with the assembly of the MB/oberaigner front diff. Its possible that the axle stub shaft is held in with a spring clip. So it can be removed with a slide hammer. If so you can replace the seal with the diff installed.
You can check the parts catalogs (subscription required unfortunately). Last I checked, they didn't break down the trans. A dealer may be able to help, may be worth a call. There are a few users here with STAR laptop units which contain the EPC data, one may post up offering to help.
That does not look like gear oil to me. Give it a wash to find the leak. Could be the turbo. There is no listing of parts for the diff, I have rebuilt a couple, the seals were standard bearing shop no delays.