Rear Noise again. Haldex or diff?

[cpu_man]

Hi guys, putting this on here incase any one else has had this issue so I can see if it's the same as mine.

I made a post a while back about having a faint whine/humm noise from the rear of the car which could be the diff?

The noise is only around 50 to 60 mph and will go away at speed how ever (this is the strange thing) the noise will only sound with light throttle (i mean very very light), if I take my foot off the gas at 50mph the noise will go, foot back on gas and noise back?

I thought diff noise would be there off the gas not off?

Could any one confirm?.

I have had a new prop fitted and I can confirm this is not the issue however with the prop shaft removed the noise from the rear goes away, so I am sure it's either the HALDEX or the DIFF but I am trying to pin point what one is at fault.

I now also have a AWD issue where i think my haldex pump is now dead and now the noise has gone.

Do you think that it's my haldex unit causing this noise or a failed diff but the noise is only there when driven by the haldex?

There must be guys on here who have had either diff or haldex issues, could I have your sounds listed to your issue?

[WarrenandZoe]

I am also having a similar issue, between 35mph and 45mph at around half throttle and above I get a humming almost whining noise, above or below that speed it goes away, also if I let go of the throttle it goes away

[cpu_man]

Originally Posted by WarrenandZoe

I am also having a similar issue, between 35mph and 45mph at around half throttle and above I get a humming almost whining noise, above or below that speed it goes away, also if I let go of the throttle it goes away

Sounds like my issue but mine is between 50 to 60mph, 52mph is its sweet spot.

[WarrenandZoe]

Would love to know what it is, all wheel bearings and drive shafts seem ok so I was suspecting with rear diff or prop bearing

[cpu_man]

Originally Posted by WarrenandZoe

Would love to know what it is, all wheel bearings and drive shafts seem ok so I was suspecting with rear diff or prop bearing

Thing I dont understand is noise goes away with the prop removed and I know it's not a prop issue.

I thought with the prop removed if it was the diff I would still have the noise with the prop removed at speed?

[cpu_man]

So little update, today I used the car for a 30mile drive and I now have no sound from the rear.

Would I be right in saying if it was a failed diff bearing (going off other people's faults with this common issue) then the noise would still be there weather the haldex pump was working or not (driving the diff input shaft)

[mcox42]

I had something similar a while back. Thought, initially, it was wheel bearings. Stealer said it was Haldex, but turned out to be rear diff bearings. Really noise between 40-60, see attached thread...

https://www.volvoforums.org.uk/showthread.php?t=293291

Cheers

Martin

[Moose Test]

I think it's a feasible hypothesis that certain worn components will only surface the symptoms (ie. noise) which you encounter when they are under load. This would explain why when your prop is removed, or effectively removed by the uncoupling from the drive source represented by the non-functioning Haldex unit, you hear nothing. Ditto taking your foot off the throttle.

I had the same symptoms (similar speed range to the op) and my resolution was to replace the final drive (diff) unit with a second-hand unit which I had reconditioned (new bearings, seals, filters etc.) by a local specialist. That doesn't show causality (many things were changed at once, including new transmission fluid) but in my case, certainly did prove that it was not attributable to any aspect of either the prop shaft or the Haldex unit which were unchanged.

[cpu_man]

Originally Posted by Moose Test

I think it's a feasible hypothesis that certain worn components will only surface the symptoms (ie. noise) which you encounter when they are under load. This would explain why when your prop is removed, or effectively removed by the uncoupling from the drive source represented by the non-functioning Haldex unit, you hear nothing. Ditto taking your foot off the throttle.

I had the same symptoms (similar speed range to the op) and my resolution was to replace the final drive (diff) unit with a second-hand unit which I had reconditioned (new bearings, seals, filters etc.) by a local specialist. That doesn't show causality (many things were changed at once, including new transmission fluid) but in my case, certainly did prove that it was not attributable to any aspect of either the prop shaft or the Haldex unit which were unchanged.

Thank you very much for the information.

This is the issue I am having trying to pin point my sound issue but as the haldex and diff are joined it is hard.

I fully understand hour point of diff pinion when under load.

Did you have same issue with sound on your diff or did you have noise off throttle as well etc?

[Moose Test]

Exactly the same symptoms as yourself. Rear located noise most prominent around the 50mph mark, under light acceleration. No noise when coasting, or under heavy acceleration.

As far as I recall now, there may have been some perceptible hint of the whine at lower speeds but much less pronounced, and nothing once above ~60mph.