Humming noise on deceleration

Have 2015 Tacoma Sport 4wd
Been noticing a humming noise on decel above 50mph after driving for about 10-15 minutes. Changed the fluid hoping this would help. Still the same. Won’t do it when first driving but once the fluid warms up and thins out it starts making noise. Thanks

 

You changed what fluid?

Where is the noise coming from do you think?
Do you feel anything in your steering wheel?
Have you had any work done to your tires recently?

 

Changed the rear differential fluid. That is where it is coming from. Nothing in steering and tires are new Michlens. Was doing it before tire were replaced as well.
Only on decel. Goes away under 50 mph.

 

Figured this out?