There are quite a few posts on this, it may not be just the seal.
The bearing could have gone as well, have a search for posts on rear wheel bearing. There was one running a couple of weeks ago.
You may need a special tool to remove the bearing and shaft.
Also check it isn't brake fluid.
Good opportunity to replace the rear diff oil, 2.9 litres special LSD oil required.
The gear oil has a very distinctive smell.
best regards, Rustic