a strange noise in the high RPM's
 

Hi guys
Yesterday while I was testing my acceleration, I reached the 125 miles per hours
After I released the accelerator, I heard a sound like the differential sound and it is fading gradually while the RPM goes down

Note : this is the only condition I can hear that sound with

I asked a mechanic friend of mine About it and he told me it is the differential but I am not sure

Any tips guys??

strange sounds are common at the 125 miles per hours

I would trust your mechanic.

Yeah but I didn't hear this Sound before

Have you been keeping up with maintenance? Differential fluid change, tranny fluid change (if manual tranmission)

Any changes to the car- modifications, etc, between when you did hear it and didn't hear it?

Did you put a tank of regular in it by chance?

Does it decrease as the RPM's drop or as the SPEED decreases? You mentioned RPM, and if it is caused by high RPM's then it should happen at any speed. Differential noise would be speed related, not RPM related.

If it is RPM related, I doubt it's the diff.