Grinding noise from rear end

I was driving down a fsr over the weekend and this grinding noise started coming from the rear end. https://photos.app.goo.gl/WjoEAwnZDETNiPBE6
It is sparstic but happens more when I am on throttle. Normaly will stop once I come to a stop or gear down. Any ideas? I'm thinking it might be the diff. Any ideas?

 

All I hear is wind noise and maybe some cymbals being playing on the radio, not anything I would describe as “grinding”.

 

What year is your truck? There was a TSB for Weeping rearends of 2016 and 2017 years. See post #1931 for that TSB.

https://www.tacomaworld.com/threads/toyota-recalling-228-000-tacomas-due-to-oil-leaks-and-possible-loss-of-control-of-vehicle.488536/page-97

 

The "cymbals" is the noise coming from the rear end. The sound is more pronounced towards the end of the video

 

2021 off road

 

It sounds more like something loose and banging around. A grinding set of gears makes a much different sound.

Also, differentials tend to make a howling noise sometimes naturally but also when worn or miss-setup. Straight cut gears and the gears in the transfer case make a similar howling sound.

 

Almost sounds like the spare tire chain to me. Zip tie the chain and throttle up and see if you still hear it.

 

The tcase is definetly bad but has been for a couple months. Planing a fj swap.
Changed the diff oil, was quite dark and a bunch of metal on the plug. I think the next step is pulling the 3rd member.

 

Unfortunatly the spare tire chain is already zip tied up.

 

I’d be surprised if that is a differential noise. Seems way too slow of a noise frequency to be diff related. Maybe a rear wheel bearing? I guess it can’t hurt to pull the 3rd member if you don’t mind doing the work. Seems like something that rotates more slowly or something not even at the axle at all to me. But hard to say.

 

Put the truck on four stands and run it in the air in 4wd and walk around the truck. It's a bit loud but kinda sounds like a loose hub cap.

As BLtheP mentioned, it could be a rear axle bearing. Mine failed and although a different sound, same rhythm and speed. Does the noise change when you do a sweeping corner at speed in either direction?