Does anyone recognize this sound? Coming from rear passenger hub area.

[CLM21]

Going to put the car up on jackstands this weekend and run the rear tires a bit to see if I can diagnose exactly what the issue is, but figured I would post here to see if someone has heard this same noise.

Because the car is completely stripped, I believe it's coming from the rear passenger hub area so I don't think it's the diff. I replaced all the wheel bearings when building this car so they all have less than 500 miles on them... wouldn't think that would be the issue. Outside of those 2, not quite sure what it would be.

https://www.youtube.com/watch?v=VcA_yavBoXc

[jbontke]

Stock diff/suspension bushings or harder materials?

[glnr13]

double check the diff bolts? I had a similar sound when 2 of my diff bolts started to come loose and caused the driveshaft to bang around the rear subframe opening. same characteristics, no sound on load but sound when coasting.

[Zambuzan]

eBay blow-off valve

[CLM21]

Stock diff/suspension bushings or harder materials?

Built diff, none of the bushings are stock. All are harder materials. I'll check the diff bolts.

[jbontke]

Does the noise only happen on deceleration? And go away on acceleration?

[CLM21]

Does the noise only happen on deceleration? And go away on acceleration?

Happens all the time, but gets significantly louder as speed increases. Almost unnoticeable under 20mph, but once you get over 30 it's very loud - especially when you're coasting and don't have the exhaust note to drown it out.

Leads me to believe it's gotta be a bearing or the diff. Haven't gotten a chance to check the diff bolts yet but I don't think that's the cause.

[jbontke]

Got an old diff you can swap in to rule it out? I have had bad wheel bearings change pitch as I loaded/unloaded them (steering the car left/right to load/unload the bearing).

[CLM21]

Unfortunately don't have an old diff. So steering actually doesn't change the sound level or pitch at all, which is partially why I initially thought it wasn't a bearing. I guess I'm leaning towards something diff related now.

[Dagamus(NM)]

Brake shield rubbing on something at speed? It is a horrible sound for sure.