LSD or Rear Wheel Bearing Help!!!! (FIXED!!!!)

[rallye_turtle]

Hi guys,

Was just wondering if there is anyone out there who would be able to assist in an issue I have with my E30. At present there is a loud hum/droaning noise coming from the rear when going above 40MPH. Its transmission related and its still there even when I let the car run in neutral at speed. Problem is I cant figure out if its the LSD or the rear wheel bearings .

Would there be anyone out there in the NW London area(mechanically minded or mechanic) who could take a look and give there opinion if i bring the car to them.

Cheers

Wayne

[toby]

Sounds diff related from here. Wheel bearings often make higher pitched sounds and and you would notice the noise coming from one side in particular (with windows open). Both rear wheel bearings are unlikely to go at the same time.

Hope you find a friendly zoner to have a look/listen.

What's the mileage on your car?

Has it been serviced and had it's diff oil changed at some point?

Is there still oil in the diff or has it leaked out?

Why is the sky blue?

Sorry I'm having an existential day...

[psychochild187]

if you can jack the car up with the factory standard car jack one side at a time
and give the rear wheel a wiggle from left to right and up and down
there should be pretty much no movement in the wheel.
keep the car in neutral and handbrake off but chock the front wheel so the car does not move

keep your hands opposite each other on the wheel so you can wiggle it . if it does not move then great , then spin it and see if it ,makes a rubbleing noise as it should rotate quietly (the disk may make some noise but this is normal)

do this to both wheels if there fine then if its not the diff or wheel bearings check the wheel nuts just in case

job done .
you only need the standard jack and the chock both from the boot of the car

[rallye_turtle]

Many thanks for the pointers chaps. I'll check the movement of the wheels tonight. Bit strange though cos the car passed the MOT a month ago and there was no advisory on the bearings, so hoping it isn't them as it sounds like a pig of a job to do, and would rather change the diff should it be at fault.

[hoshy]

Are the rear wheel the same sizes? If not then that can cause funny noises from a slip diff.

Also double check that it's got the proper castrol oil in it - I used comma lsd oil and it made the diff a bit noisy.

If you can get the car properly secured and run it in 2nd or 3rd with the rear wheels off the back you might be able to locate the noise a bit better.

If it is wheel bearing then a whole trailing arm is quite an easy diy swap.

[rallye_turtle]

Thanks Hoshy, I've bin meaning to check the LSD oil, I'm hoping that this may help the issue If I get some of that Castrol SAF-XJ stuff.

[harry_p]

does the noise get louder or quieter when cornering?

a worn bearing will often drone louder when it's loaded up, although sometimes they quieten under load which can make choosing which one has gone a bit tricky.

recently had a noisy front bearing on the other halfs golf, we were both convinced it was the drivers side that had gone so i changed that, went for a test drive and it was still exactly the same!, changed the other side and all was good with the world

[rallye_turtle]

does the noise get louder or quieter when cornering?

a worn bearing will often drone louder when it's loaded up, although sometimes they quieten under load which can make choosing which one has gone a bit tricky.

recently had a noisy front bearing on the other halfs golf, we were both convinced it was the drivers side that had gone so i changed that, went for a test drive and it was still exactly the same!, changed the other side and all was good with the world

It seems to quieten down when I slow down and doesn't really change when cornering.

Just checked the fluid in the LSD a few mins ago and its up to the correct level (level with the bottom of the filler hole), the fluid is a yellowish colour and tastes funny too (joking) what colour should the fluid be??

Also jacked the car up and checked for any play on the rear wheels (had handbrake down and in neutral) which there wasn't any. Will a worn bearing always give play??

[stonesie]

No not always, when my rear wheel bearing went there was no play in it but it felt a bit rough when the wheel was rotated by hand.

The noise it made changed with cornering too, with yours having a LSD it will be harder to rotate just 1 wheel so what I would do is to get the back end up on axle stands with the front wheels well chocked and let the engine idle in 5th, that should spin everything upto about 20mph so you can get under there and locate the noise.

Be aware that the moveing parts will not stop for you.

[rallye_turtle]

Just had a thought, when I was checking the wheels for play earlier, I was able to rotate the jacked up wheel while the opposite wheel was still on the road. This shouldn't b possible with an LSD right....?

[psychochild187]

its possible on a worn out lsd , also worn lsds can make funny noised when doing slow tight turns (eg parking at tescos)

[rallye_turtle]

I suppose it may be worth chucking in a cheap open/diff as a temporary measure to see if this sorts the problem out, and then buying an LSD when one shows up.

[rallye_turtle]

Just had a thought, when I was checking the wheels for play earlier, I was able to rotate the jacked up wheel while the opposite wheel was still on the road. This shouldn't b possible with an LSD right....?

I guess with what I said, I can probably presume that the LSD is buggered, and an oil change may not help??

[rallye_turtle]

Well after a few months of trying to diagnose the problem it ended up being the passenger side rear wheel bearing. Bought the part on a hunch that it might of been that, took it to my mechanic and sure enough it was just that. Bit strange though as when checking the mentioned wheel there was no play at all and didn't show the typical symptoms of a worn bearing, but the mechanic assured me that it was. Cost a bit too at £180 for labour . Got the car back this morning and the noise has vanished, even feels smoother whilst cruising, anyway alls good

Cheers