Please somebody can help to determine what is the source of this leak and how could it be fixed?
It's a small leak, it doesn't even drop to the floor. The problem is that, when the drive shaft spins, the fluid is spread all around and then builds up an awful sludge everywhere. It's a yellow-ish oily fluid, it is not ATF nor motor oil for sure, it seems to be diff oil. I've read almost every post in this forum about pinion seal leaks, but as you can see from the pictures, the front diff assembly is completely dry. The only wet spots are those marked in red circles exactly between the companion flange and the front drive shaft. Thats why I'm asking, I really don't know where does that fluid come from.
In order to locate the spot, removed the skid plates and got the under body thoroughly cleaned. You may note that the boot is also clean and dry.
Here is the transmission skid just after removing it:
What do you think? Is it an easy one? Would it be very expensive to get it fixed?
As always, thanks in advance for your help.