1999 LC : Troubleshooting a " wine" sound

[jayfrem]

Hello

Have an LC 100 with 147 K Miles.
I am running 285 75 16

I think it has 4.3 Diffs code on engine bay is " A04 B"

I heard a lot that 1999 Front Diffs are weak.

I do hear a hum when on the highway at 45 MPH.

Could it be wheel bearings ?
How to know if it is diffs ? There is not much sound at deceleration when i take my foot off the gas.

Jay