DB9 rear end whine

[Hutch525]

After a little bit of help....

Before Christmas the engine on my Range rover blew and its now at the garage being rebuilt.
I've had to use my (2004) DB9 to get to work every day ( I know such hardship ) 120 round trip.
Problem its its has developed a whine from the back end and has got louder over the last 2 weeks

Diagnosis so far :
Whine only happens with light pressure on throttle or on deceleration
Whine is linked to road speed, gear doesn't matter nor does revs.
Whine does not increase or decrease with left/right cornering or straight ahead.
Noise seems to be coming from left rear ( sitting in drivers seat)

I'm having the rear tyres changed Friday as its the cheapest thing to start with.

Has anybody had a similar issue?
If so has it been anything other than the rear Diff?
( don't really want to have to replace that )

Thanks in advance

[Matt_E_Mulsion]

Could it be a wheel bearing?

[Hutch525]

That is going to be the next change after tyres.
But, i've had a rough wheel bearing before and it got louder/quieter when going round corners and it doesn't do that

[paulrog1]

I'd also get the rear diff oil changed, make sure you put in the Kendal additive.

After that I'd look at the wheel bearings, you can get cheaper Firstline ones but just as good as AM parts, the job is easy but biggest problem is pressing the half shafts out.

Good luck

Edited by paulrog1 on Wednesday 26th January 09:13

[Matt_E_Mulsion]

Hutch525 said:

Diagnosis so far :
Whine only happens with light pressure on throttle or on deceleration

Rereading this, that doesn't sound likely to be a tyre or a wheel bearing.

[Hutch525]

Thanks for the feedback gents.

Diff oil got swapped out on the weekend with no difference In noise.
Going to try tyres as relatively cheap.
Halfshafts I've already had out at the weekend, couldn't feel grumbling on the bearing un loaded and half shaft was solid with no play.

Clutching at straws with options before I go get the diff rebuilt

[David W.]

What did diff oil look like or did it just get drained into a “common” catch can?
Not sure of the cost but it could be analysed for metal content.
Some people also support additives to quieten diffs and gearboxes.

[embdenb]

This has all the symptoms of a diff pinion pre-load problem. As you modulate the accelerator, it changes the pinion pre-load and thus the angle of the pinion gear against the crown gear. I know it’s a transaxle with the dif and gearbox as one unit. However I believe inside the transaxle somewhere that correlation between crown and pinion exists. I suspect a re-build is inevitable.