Noise upon deceleration... differential problem?

[Indiana80]

I ruined my front diff earlier this year, and your symptoms sound identical to mine.
Mine started whirring 1000+ miles from home. The next day I topped off the front diff and it took about 1 quart of oil, so it was very low. Drove it home RWD with the front driveshaft removed. The bearings and gears were toast, so I bought a press and rebuilt it.

Was your noise one that could easily assumed to be tire noise (not metallic) that began around 20-25MPH and disappeared at highway speed? Kind of a ghostly low frequency whoohwhoowhooh in the cabin that you really only hear with windows up?

 

[LX470MN]

Was your noise one that could easily assumed to be tire noise (not metallic) that began around 20-25MPH and disappeared at highway speed? Kind of a ghostly low frequency whoohwhoowhooh in the cabin that you really only hear with windows up?

The main difference is that tire noise would happen in any load condition (accelerating / decelerating / neutral).

The noise that I experienced was only audible when accelerating or decelerating. If I applied just a little throttle (to take the load out of the drivetrain) the noise would go away.

 

[Indiana80]

Mine turned out to be toaster front diff, also. Exact same symptoms as yours. Thanks OP for all the diagnostics and video…large cost to replace, but saved me a lot of time and frustration of throwing parts at a terribly annoying woowoowoowoo noise .

UPDATE: dealer that diagnosed my noise as bad diff, came back and said not diff- tire noise. I swapped a new set of less aggressive AT tires (Yokohama), and the noise is almost gone.