Possible Diff issue

[Beatman]

Following a joyous drive the other day, whilst passing parked vehicles and buildings. I noticed a whining noise from around the rear of the Z.
As I slowed the noise stopped, I checked around the car, but nothing. At the weekend I had both the rear wheels off along with the discs. But nothing loose, or play in the bearings..
Went for a quick test drive, and back came the noise. It's definitely speed related, both up and down. Tried in and out of fear, clutch in / out. But the noise remains. :thumbsdown: starts at around 30mph and stops at about 25.

Anyone have any thoughts on possible issues?

 

[1000rr]

I had no play in a noisy wheel bearing, but it whined like my missus.

Changed it, all good.

 

[MACK]

It would be unusual for the rear diff used with the M54 engine to fail, unless its been leaking and lost all its fluid etc. As above i'd be looking at the rear bearings and even the tyres first, although I would expect more of a rumble than the whine your describing. That said its surprising the noises a tyre can make. What tyres have you got on the rear and how much tread is left?

 

[Greg 01]

+ 1 .
For the tyres making very strange noises .

 

[Beatman]

It would be unusual for the rear diff used with the M54 engine to fail, unless its been leaking and lost all its fluid etc. As above i'd be looking at the rear bearings and even the tyres first, although I would expect more of a rumble than the whine your describing. That said its surprising the noises a tyre can make. What tyres have you got on the rear and how much tread is left?

MACK , this is a definite whine, it difficult to explain what exactly it's like. I'm sure it's not the tyres as it started the other week and I have changed the rears since then, so both old and new tyres.
If I could figure out how to add a YouTube link you could then hear the noise, as someone has posted a short clip..

Been out tonight and it starts at around 45 stops ate 20-25. Very odd.

 

[Beatman]

I found this vid on you tube, this is exactly the same as the issue I'm getting.,, hope the link works

[youtube][/youtube]https://www.youtube.com/watch?v=RvHSwrMMHqI&feature=share

 

[Beatman]

Bump ?

 

[andyf1140]

Doesn't sound like diff or bearings to me, but I can't offer an alternative though :?

 

[andyf1140]

It doesn't sound like tires either, could it be something rubbing against the tire, wheel or reluctor ring?

I have had this happen a couple of times and it sounded like a bad wheel bearing, the first time is was a mud flap on a rally car and the second was a twig trapped in the wheelarch on a Focus.

 

[MACK]

I have to agree with andyf1140 it doesnt really sound like diff or bearings to me if its like that vid. It sounds to me like when something is catching rubbing on the tyre. Id be checking like andy says and seeing if things like the rear springs intact and the tyre's not catching the arch liner etc. that sort of thing.

 

[Beatman]

All, I've had the car up on a ramp. And to the eye I couldn't see anything obviously wrong or rubbing.
The car has just passed mot, so sure a spring would have been picked up.
It is an odd one, so hoping not a diff issue. But sounds exactly as the video

 

[charlie8]

It does not seem to change pitch with more speed in video, does yours ? WHat about when going round left/right turns when it sounding, any difference as that will change the internals of the diff obviously ?

Almost like something starts to happen centrifugally, so starts stops at that speed or maybe even wind speed, guess the brake back plates are secure, they are thin metal and might rub on something, but a long shot

Any more heat on the hubs on one side, what about different gears - still sounds comes on at same speed ? That would suggest its road wheel speed not diff internals ( I think ) and so not diff

 

[Beatman]

Charlie8 , thanks for your reply. It seems to stay fairly constant noise wise even if you do turn left / right.
As mentioned starts above 30, but defo stops at approx 25mph.
Tonight I tried swapping wheels, but with no luck. But it does sound as if it's more drivers side. But when driving it is difficult to lean over the passenger side window .
I may purchase a rear wheel bearing and swap to see what happens. But having just passed mot, I thought they may have picked up any wear / play.
I must thank all the members who have replied so far, as any suggestions are greatly received.

 

[andyf1140]

Could it be something rubbing on the ABS ring?

 

[Beatman]

Could it be something rubbing on the ABS ring?

andyf1140, I did take your earlier advice ref the reluctor rings. But I can't see anything that shows signs of wear or rubbing.
After spending many hours trawling the net, I think my first swap will be the wheel bearings (rear). Even though nothing was picked up at the mot.