Sound from 35ish-45ish mph

[seoulstice]

I have a strange resonance coming from somewhere in my drivetrain between 35-45 mph...it's a humming noise and I can't quite place the source [if it's coming from the front or the back]. thought it sounds like it's coming from the front. However, I can't be sure if the resonance is playing tricks with my ears and it's in fact coming from the rear. I'm wondering what is exactly wrong with my vehicle.

1) My driver side rear axle seal has been leaking for a few months which I am going to remedy in the next few weeks. The bearing hasn't been grinding and I'm wondering if the noise is in fact coming from the rear due to this.

2) I have semi-aggressive tires[Cooper Discoverer ATPs] which I had installed in the Spring, however I don't remember the noise back at the time of the install, I think it started after. Also, I don't think they're aggressive enough to make this much noise.

 

[fourwd1]

OK, is it just a noise, or are there vibrations too?
Vibes at specific speed range are usually due to out of balance tires.
Noises, on the other hand, are a little harder to figure out.
The hollow drive shaft acts as a conductor, sending sound from one end to the other, making it harder to pin down. You may try getting the vehicle in the air and rotating each wheel by hand, and maybe track down the source.

 

[seoulstice]

It's definitely a noise, I tried to take a video but it didn't capture the sound well - I'll have to give it another shot. The noise is there before 35mph too but just not as pronounced. After 45mph it just goes away or is too high pitched for my ears to pick up.

 

[seoulstice]

It's basically a loud humming.