Rear Noise again. Haldex or diff?

[Moose Test]

I'll add to the above that I think it's very difficult to differentiate between noise from the Haldex unit and from the final drive, period, since they are tightly mechanically coupled through their casings.

I took my car to Holden Volvo in Norwich, who I think were very good. The service manager let me sit in the car with him whilst we drove around, with microphones attached to both units. Switching between the two audio channels it really was impossible to say definitively from which the noise was emanating.

In the end, I went with replacing the final drive first, on the basis that I felt it was the most likely source, containing pinion gears as it does. A guess which luckily paid off. I sourced a new final drive myself (eBay) and had it reconditioned, with Volvo fitting it (a Volvo reconditioned unit would have cost around 2500 GBP). That worked for me but I'm really not in any position to even suggest that's your issue too.

[cpu_man]

Originally Posted by Moose Test

I'll add to the above that I think it's very difficult to differentiate between noise from the Haldex unit and from the final drive, period, since they are tightly mechanically coupled through their casings.

I took my car to Holden Volvo in Norwich, who I think were very good. The service manager let me sit in the car with him whilst we drove around, with microphones attached to both units. Switching between the two audio channels it really was impossible to say definitively from which the noise was emanating.

In the end, I went with replacing the final drive first, on the basis that I felt it was the most likely source, containing pinion gears as it does. A guess which luckily paid off. I sourced a new final drive myself (eBay) and had it reconditioned, with Volvo fitting it (a Volvo reconditioned unit would have cost around 2500 GBP). That worked for me but I'm really not in any position to even suggest that's your issue too.

Was yours the sane, around 50mph you would get a light whine with foot on gas, once foot off noise goes away?

[Moose Test]

Originally Posted by cpu_man

Was yours the sane, around 50mph you would get a light whine with foot on gas, once foot off noise goes away?

Yes, to my best recollection, just as you describe.

[WarrenandZoe]

Mine is the same but at lower speed, if I switch to manual (geartronic) it makes no difference what gear I'm in either, it's speed and throttle that affects it

[laundryman]

Having had this problem on a Selekt car, after changing all the engine mounts and changing stuff on the rear diff, they removed the prop shaft and the noise went. so replaced prop shaft. job done. from your post:
Thing I dont understand is noise goes away with the prop removed and I know it's not a prop issue.

You have diagnosed the fault!!
there are a couple of sets of spider couplings and a centre bearing on prop shaft so could be any of those. Has shaft balance weight come off?

[cpu_man]

Originally Posted by laundryman

Having had this problem on a Selekt car, after changing all the engine mounts and changing stuff on the rear diff, they removed the prop shaft and the noise went. so replaced prop shaft. job done. from your post:
Thing I dont understand is noise goes away with the prop removed and I know it's not a prop issue.

You have diagnosed the fault!!
there are a couple of sets of spider couplings and a centre bearing on prop shaft so could be any of those. Has shaft balance weight come off?

No as I fitted a brand new prop and noise is back.

I would say the diff is not being put under load without the prop causing the noise to go awaym

[cpu_man]

Ok guys going to remove my diff.

Will update as I go along

[cpu_man]

Ok guys so diff is out and haldex removed etc.

Here is a link to the main input bearing, sounds like the bearing is worn out.

https://www.dropbox.com/s/xyyamida3r...20936.mp4?dl=0

[cpu_man]

Hi guys, sorry for the delay as not had chance to work on the car.

So I had removed the rear sub frame and rear diff and sent it away for repair.

I can confirm my nose bearing on the diff had failed causing my noise issues.

The car is back together and is super quite now so all good.

The company I used is below and I can recommend them for a diff rebuild.

https://rover.ebay.com/rover/0/0/0?m...2F273440497469

I have another xc90 I am doing for private job that will have diff removed and rebuilt etc, if any one requires any help or information let me know.

[kiwiV8]

just registered to say thanks for this post, I seem to have quite similar issues except I get the droning sound when coasting too... do you know if there're variants of diff? I am thinking of doing what you did, just buy a used one online and get it sent to a shop to get it rebuilt then ship it over here. The local dealership thinks I'm a billionaire!