Rear axle is soaked, need help...

[Waterloo]

To dark to work on it tonight... Pretty sure it is that pinion seal, it is heaviest right there and then washes out from there, but will still clean it off and drive before tearing into it in case it is coming from the case itself... Anyone know the size of the input shaft nut and the torque specs? Anything special in regards to tools I will need to install that seal if it all checks out? Like a seal installer? Or just make my own? Never done one, but seen it done a few years ago up in the oil field...

My head is spinning right now, a lot going on and the clock is ticking...