Seeping Differential but behind it, at drive shaft

Hi. I have an 07 ram, 5.7 hemi, 4x2, crew cab(ex cab I think you call it). When I was swapping the rear speed sensor into the diff the other day, seepage was happening behind the differential. The back side, where drive shaft connects.

No leaking on the bolt side of it, just other side. It's not really leaking, like not dripping or nothing, but the seepage has built up a bit. Little worried now.

I got a 98 larimie w the 5.9 and it's a 4x4 and when I changed the dif fluid in it a while ago, coincidentally, the transfer case started to "pop" out of 4 lo, into neutral. I used Chryslers friction modifire(i think you call it) and some Valvoline fluid from AZone. It's prob a coincedence. But before I tackle whats happening with the 07's 4x2 diff, I wanted to see what you think's happening, maybe what to do afterwards for the "cure"!

I'm trying to leave pics but 1st post ever(been lerking and searching for long time, just never posted anything) So not sure if the pics work or not. Lmk if not. Heres what I think youre supposed to click to see them. Btw, I used to be able to simply put a pic in a post with this dropbox thing I've been using for a long time now, but, they changed how you have ot share a pic. They ,make you create a link now, then paste that link to somewhere. Hmm. Not so sure bout that one but...here it is, hope it works!
https://www.dropbox.com/sh/032yv4wiojchfyn/AACoJGZBZr8bN7x6Sz4zQk6va?dl=0

Thx for any input, guidance!

That sounds like the pinion seal is leaking.

^Yup, that's your pinion seal dude.

Unless it gets worse, or you get an actual drip. I wouldn't worry about it, that slight seepage is not a problem.

I have same thing. One day I'll fix it.
Just keep an eye on it and the fluid level.

Ok, so it's the pinion seal! Cool. Thanks for that! At least I know whats going on now!

I checked fluid, it's just below the bottom of the fill hole. Then cleaned "fur" off of cover.
It was sort of thick though. More "sludgy" than "furry" so to speak. Not like "fur" you see on vc's sometimes.

Seriously happy you all don't seem as if it's too critical at this particular point too, that's for dmn sure!

And y'all don't think I should change pinion's seal? I guess hotkarl did say only to keep eye on it. Like meaning 'dont' freakin mess with till it's worse than this(I think). But maybe, like if I see a drip, I should get ready to plan on taking care of it.

When I put shift lever seal on the 98 Ram's trans, getting that seal either out or back in was a btch! Cant remember which.
Is pinion seal bit more difficult that shift lever's seal, ya think?
Btw-
It's got 159k, would y'all drain & fill at this point? 75/140? Or u think that'll make pinion seal start to get worse?

Thx for responses! Big help.