Humming sound / new rear main seal

Just replaced the rear main seal, by the book. I haven't driven the jeep yet but on idle I hear a light humming sound coming from the RMS area. Anyone else run into this? Normal? Seal breaking in? It definitely doesn't sound like any type of metallic on metallic sound...that's why I'm assuming its the new seal?

Thanks!

Don't see the relationship of seal replacement and humming. Could be coincidental to the repair; might be something else.

I'm assuming you've driven it by now. Noise still there?

Found some time to tinker with it...turns out it was JUST coincidental, the alternator is bad. Good news for me...didnt want to take the pan off again! Thanks guys!