Low Speed Humming

I’ve noticed that in my front driveline, there is a noticeable humming that can be heard and felt under 40 mph.

I don’t think it’s a wheel bearing. It’s more prevalent during colder temps.

The front diff and transfer case has been drained and filled in the last few thousand miles.

Where should I start?

 

first look for leaks, raise a tire, spin it and listen, check for bearing wear by tilting tire vertically.

 

I would read this post first.

"Front Diff Vibes ECGS bushing fix"