I have a vibration when my 2006 LR3 is coming off fast idle. It happens at 1100 -1200 rpm only.

Also, I have a slight vibration in the steering wheel. I recently changed tires and have Kumho's on now. I will take it back to Discount Tire and have them rotated and balanced, but I don't think that is the issue. Feels like it is "deeper" than that.

How would I know if one of the differentials is going out?

 

My rear diff hums

 

Hmmm, does it hum anything in particular?

Could be multiple issues.

On the fast idle thing, have you cleaned your throttle body?

 

Does it happen at a certain speed? See what speed it happens at and then try it again but this time in neutral. If it's the tires it should reproduce the issue whether or not the vehicle is under a load.

 

Need a lot more info here.. is it speed dependent or RPM dependent? Ie. does it vibrate with the revs of the motor? Or with the speed of the tires/car?

Is it a high frequency vibration (think electric razor) or low frequency "thud" like traditional wheel balance issue?

Does it change when you apply gas? These cars have some driveline issues where all NVH disappears when you remove throttle, but as soon as you apply enough gas to maintain speed, the NVH comes back. Mine does this through steering wheel and driver floor.. HF noise I can hear as well.. but if I take my foot off the gas it's gone. This has happened on two different 06 rovers (RRS and LR3) with totally different tire setups.

For ME I'm thinking wheel bearing, but your problem might be more basic like wheel balance.

We definitely need a lot more info tho.