Rear end harmonic noise

[Mustangdave]

I have a 2011 Limited with 112k miles. At around 50mph, I hear a harmonic noise coming from the rear end. Also, the 4LO, ABS, Brake, and Traction lights flash sometimes. I changed the rear diff fluid and greased the driveshafts in hopes that those had something to do with it. Could it be the rear bearing/hub? I've done a lot of research and can't find any write-ups on how to replace the rear bearing/hub if that's what the problem is. Thoughts???

 

[Twilghtzone]

What produces the noise ?

1) At speed, backing off the throttle ?
2) Going downhill at speed ?
3) Noise is all the time ?

 

[GripT4R]

There is a youtube video on how to replace a rear bearing/hub and abs sensor

 

[Mustangdave]

What produces the noise ?

1) At speed, backing off the throttle ?
2) Going downhill at speed ?
3) Noise is all the time ?

The noise happens at around 50mph. I can put it in neutral and the noise continues so I know it's driveline related.