well the seal can be replaced from the front but most of the time the problem is the pinion is bad, replacing the seal alone has pretty low odds of fixing the problem.
you can drop the drive line and grab it and give a good wiggle if there is any play at all then it's time to replace the pinion and that's a bit of work and it has to be set properly or it will just fail again.
you have to remove the brakes, remove the axles, pull the carrier out and then you have access to the pinion
I'll drop it in the morning and give it a little wiggle.
I don't have the tools or knowledge to do that kinda work, never worked on any rear ends before. I'll have to drop it off at my mechanic for that.
From what I've seen it could be a warn seal, at least I'm hoping that's all it is.
One thing I've noticed since we've moved to the coast is the heat/humidity and just how strong the sun is, it's amazing how much of a difference there is compared to inland just three hours away.
I'll be back in the AM with an update.