How to locate differential noise?

[markus_74]

Hello,

I'm confuse is it my Differential that cause noise or my new tire?

I try to make a test, while my car down hill I put my gear on neutral and I also press my clutch(not necessary), I hope it is disengaged my engine from connected with gearbox and my diff.
The results the noise is still there and the loudest is at 40km hour.
I can not make conclusion is it my diff or my tire that make noise?

Or any better method?

Thank you
Markus

[Contours]

Differential noise usually starts at 40mph and gets louder as you accelerate and sounds like a loud drone coming from underneath the car. You should check to see if there is oil in there.

[Brianmoooore]

Tyre noise should change with different road surfaces.