Humming at highway speeds 55 to 60 mph.

B

blackcx9

We are having an issue with a humming when you are driving between 55 and 60mph and you let off the gas or you if have the cruise on it is there constantly. We have taken it to the dealer and they replaced the Transfer case but the noise is still there. We don't hear the noise at slower or faster speeds which is really strange. It is a AWD CX9 Grand Touring. Any one having this issue?
 
We are having an issue with a humming when you are driving between 55 and 60mph and you let off the gas or you if have the cruise on it is there constantly. We have taken it to the dealer and they replaced the Transfer case but the noise is still there. We don't hear the noise at slower or faster speeds which is really strange. It is a AWD CX9 Grand Touring. Any one having this issue?

I also did experience in my CX9 sport FWD when accelerating or going at low speeds. What is this transfer case BTW ?
 
It transfers power from the front to the rear wheel in a 4 wheel drive vehicle.
 
My wife and I have noticed that in her CX-9 as well...didn't think to have it checked out as I just assumed it was in the transfer case or was just a typical noise I could expect to hear. After looking around online I have found that there has been many compliant of this noise but no solution as of yet.
 
Not sure if it is the same issue/noise, but last weekend I noticed a vibration, which felt like it was coming from the tyres (like small road surface currugations) on a smooth piece of road. The vibration is strong enought to feel through the steering wheel and through the body of the car, but doesn't feel dangerous.

At first I thought that I had picked up something in a tyre, like a bolt or stone, but when I checked, nada. The vibration went away, but would come back again occaisionally and I haven't yet found a perfect speed or condition to duplicate it. I have an Australian CX-9 luxury (AWD).
Gibbo
 
We are having an issue with a humming when you are driving between 55 and 60mph and you let off the gas or you if have the cruise on it is there constantly. We have taken it to the dealer and they replaced the Transfer case but the noise is still there. We don't hear the noise at slower or faster speeds which is really strange. It is a AWD CX9 Grand Touring. Any one having this issue?

It'll be your tyres (aka tires). I had exactly the same issue, and you've probably also got the GT with bigger wheels. Check your pressures, and also make sure you are running air and not nitrogen. I had exactly the same groaning noise. Felt like it was coming from the tranmission, and I could even feel it through the shifter.

Turned out that when my tyres were repaired after a puncture the garage had used nitrogen (which is at a higher pressure, but does not expand due to temperature as much). Mazda removed the N2, put good old air in, and the problem went away.
 
Thanks AndyDove21, that could explain my problem. Could you expand the cause a bit please? ie; is the humming caused by too much pressure or too little pressure when the tyres warm up?

Cheers,
Gibbo
 
It'll be your tyres (aka tires). I had exactly the same issue, and you've probably also got the GT with bigger wheels. Check your pressures, and also make sure you are running air and not nitrogen. I had exactly the same groaning noise. Felt like it was coming from the tranmission, and I could even feel it through the shifter.

Turned out that when my tyres were repaired after a puncture the garage had used nitrogen (which is at a higher pressure, but does not expand due to temperature as much). Mazda removed the N2, put good old air in, and the problem went away.

I'm having the same humming problem.. when going between 110km and 120km, would the tires pressure fix the problem?

I have the 20" ring the big ring

please provide us with more info

Blueyo
 
Its not the tires, there is nothing wrong with the tires.. its something under the rear seat on the driver i dont know what could be the problem.. but i know that my friend has the same sound in his CX-9!!
 
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