What am I looking at?

[rScotty]

Looks to be an axle seal replacement. Often the bearing is good. Sometimes seals just give up.

I'd start by looking in a parts book. You can usually use the exploded diagram to tell how to approach the seal. On most tractors that seal involves taking the rear end apart enough to loosen the axle so it can be withdrawn. The seal actually goes on from the inside.

A simple job, but a heavy one & with lots of bolts to deal with. Lots of grease and not a few gaskets.

Try to figure out where the axle sits relative to the fill line on the dipstick for your rear end fluid . It may well be that you can run it as is with an occasional topping off for years for chore work while you decide what to do.
rScotty

 

[DK35vince]

An axle seal isn't that bad of a job.
I did one a couple years ago on my machine.
Some parts are a little heavy is all (my rear tires are loaded, but it wasn't a problem)

 

[TractorGuy]

Make sure you don't have a clogged vent first. A common cause for leaks is excess pressure.