My 09 XKR has a strange humming noise which sounds like it is coming somewhere from the passenger side rear end. It sounds a bit like a wheel bearing, but I pretty sure it isn't because it only happens when I have the throttle in a certain position. I can turn it on and off like a switch with my right foot!!

Does anyone else's Jag do this?

Thanks, Gordon

 

Keep in mind, you will never get a sure fire answer online to a question aboit an odd noise or vibration. The most reliable info will be general areas of inspection, but nobody is going to say it is X... especially when you don't mention any conditions other than it happens at some point in the pedal travel. Video can be of some help, but microphones can't pick up subtle harmonics that a trained human ear will, so it's no guarantee of getting you any closer to a solution.

That having been said, here are some tests to perform:

On a smooth road, weave left and right and listen for changes. If the noise increases when going left and disappears or reduces when going right, it's probably your right wheel bearing. Vice versa for the left wheel bearing.

On a smooth road at a speed the noise occurs at, put the transmission in neutral and vary the throttle slightly and listen for change. If no change, it is not throttle dependent and the source will be somewhere aft of the transmission output.

If there is a vibration associated with the noise, pay attenation to that as well. If it's a low speed vibration, it's going to be between the differential and contact patch of the tire. If it's a fast vibration, it's going to be between the transmission and the differential.

At this point, you should have isolated to a general area where the noise is coming from, and from here on out will require exploratory surgery to back up the suspicions generated by testing.

 

Thanks for the input Mandrake, but the noise is throttle dependent. The tests you've mentioned I've already done, and it makes no difference to the noise. Only the throttle position changes the noise, and there are no other symptoms or vibrations. I know it is almost impossible to diagnose it on a forum, but I was hoping someone may had come across this before.

 

Youre welcome. These sort of things are what I really enjoyed back when i worked on cats for a living. Does it only do it while driving? Or will it do it in neutral or park in your driveway?

 

I have whining noise between 10 and 30 miles speed. Seems to go away after 30 mph. I am suspecting steering wheel pump. The Jag mechanic thinks it is Supercharger.

Still waiting for the final verdict.

 

Maybe it is humming because it doesn't know the words?

 

Is that your good foot?

I had a similar situation with the rearend on my Suburban. It would only do it on the pull/load of throttle. But it was more of a drone/hum. Rebuilding the diff discovered a bad bearing.

 

 

Willya look at that. I nailed it in just one try and one sentence.
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