Rear pinion seal replacement and an OOPS with Vent Hose

[chevymotocross]

While getting the broken rear upper shock mount out of my truck, I wanted to take a peak at other stuff while I was under there. The rear end has slung fluid underneath the bed, pretty messy. Also I need to replace the u-joints.

It appears to be a pinion seal leak but usually don't these drip fluid down to underneath the rear end? This leak, the fluid gathered around the pinion flange nut, not really dripping downwards like I've seen on other cars. Either way, it must be the pinion seal since that's the only seal in that area correct?

The nut and shaft are slotted in 3 positions to line up. I will count the number of threads and mark the flange so I can line it up and get the nut exactly back to where it is. Is this a safe way to do this? I know the torque of the pinion nut is extremely important.

Also, I did an OOPS with the rear-end vent hose. I wanted to make sure it was venting (due to the leak). Well, I know now that it is venting but in the process of carefully taking it off, the vent snapped flush at the axle Anyone run into this and are there any decent fixes? I was thinking epoxy to mate the hose to the axle body (while of course making sure excess doesn't plug the vent).