Noise from the rear!!

[craigbeal]

So always had some noise for the rear of the car the past year I've owned the car..

Had the wheel bearings replaced not longer after I've had it and never really made much difference.

This is definatly a mechanical / metallic noise so not tyres/road noise.

When at a stand still engine sounds sweet as a nut.

Sound changes / louder with speed, with clutch in / out out at speed stays the same as does with in gear or not, makes no odds.

Doesn't change in sound if brakes are applied or not.

I did a diff oil change last week and this made what little diff noise there was from the rear at the time almost go entirely.

And new disks all around a few weeks ago but can't imagine its linked to the rear hand brake maybe (although that hasn't been holding as well as it did I noticed today, might just be a coincidence) but again the sound doesn't change if brakes applied or not at this point.

Now the noise is LOUD and doesn't sound good at all, almost a dry metallic sound like a failed bearing?!

Any ideas what else it could be? Diff, Drive shaft, do these parts all have bearings I assume that can fail?

 

[craigbeal]

An update,

Got the car onto axle stands today and ran the car off the road to get under it and listen to where the sound was actually coming from.

Its certainly the diff area so rules everything else out. Now just boils down to if its the diff internals or a bearing of some sort (I think it sounds like a bad bearing kind of noise) so going to have to get it booked in somewhere for a repair :/

 

[DamianPinder-George]

I'd agreed with it being a worn Diff (or Final drive). Now, my understanding is that the Zed final drives are pretty good for reliability as the mileage rises but you may have one that had a poor childhood and its affected it later in life. As someone who's blown up more 2nd hand Classic Rangy diff's than I care to remember, I'd say that the culprit is the small pinion bearing at the front of the diff where the power comes in from the propshaft. They can be poorly and still rumble on for ages before going bang.

 

[craigbeal]

I'd agreed with it being a worn Diff (or Final drive). Now, my understanding is that the Zed final drives are pretty good for reliability as the mileage rises but you may have one that had a poor childhood and its affected it later in life. As someone who's blown up more 2nd hand Classic Rangy diff's than I care to remember, I'd say that the culprit is the small pinion bearing at the front of the diff where the power comes in from the propshaft. They can be poorly and still rumble on for ages before going bang.

Thanks for the input.

From what I’ve read the more i agree it sounds like a pinion bearing, apparently the N52 engine cars suffered with the going at about 70,000 which mines just gone over so would make sense.

Also after the diff oil change 3 weeks ago the whole diff sounded better but I had just started to notice a light bearing type noise a week before but other than that was all ok. It’s like the diff bearing suddenly got bad quickly which I can’t imagine the diff itself going that bad that quick.

Will get it to a bmw specialist down the road and see what he thinks.