Recently my 2008 LR2 petrol (156,000 miles) has started making a noise from the front of the car whenever I turn right, Or put it in reverse and hold the break. If I let off the break in reverse the noise stops, it also only does this when it is cold out. The noise is louder than the engine and is really hard to place, it sounds like a loud mid pitched hum or maybe a pump struggling. At first I thought it was just my motor running poorly. I had a shop try to find briefly (they were replacing a wheel bearing) they said it was coming from the front differential/PTU. This makes sense with the turning right and being worse when cold. But I do not understand how it could be my diff when I'm holding still in reverse. I will be changing the fluid in my diff shortly, but if anyone knows anything that could help please let me know!!

 

check the PTU while you're at it.

 

What is there to check on it? like leaks or obvious axel slop?

 

or noise! She may be worn demanding a new one or a rebuild.
I’ve learned that it costs about the same either way but the replacement path is a 1/2 day turn around.

 

In reverse it could just be the engine firing tacking up the slack in a bearing on its way out.

 

I'm pretty sure that the prop shaft which goes from the PTU to the haldex on the rear diff could be spinning.

Power needs to be available to the haldex/rear diff in case the front wheels slip, in which case the haldex engages and connects the shaft to the rear diff.

So it would make sense to me that part of the PTU and the prop shaft would be turning when the brakes are held.

 

Update: I started my 2008, set the park brake, and put it in reverse. The prop shaft did not rotate.

So either the prop shaft only rotates if one or both front drive shafts rotate or it's locked out with the park brake on. Didn't have a helper to try it with foot brake.

 

Hi there, did you find out what the root cause was? My wife's 08 lr2 is having the same exact symptoms, slight right on the steering wheel you can start hearing it, and its louder on the first start ups.