Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: Alex W on 28 May 2014, 17:13:44
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I have a whine that must be coming from the diff. Its not a loud noise but it is annoying. The sound began suddenly from nothing a couple of weeks ago it starts at about 30/35 mph, below that speed there is nothing.
Tyres, brakes and wheel bearings all OK.
Question: Is this something that might be eliminated with a simple diff oil change or am I going to have to source a replacement diff?
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Actually its more of a hum than a whine
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I always wondered what happened to the noise to Bob Dents mv6. He thought it was dif whine, but I thought it was exhaust whistling. Tbh.
Maybe Jimbob will be along, as he owns the car now, last I heard.
Dif whine, I think 2woody said, relates to shimming of the dif. Iirc if its too tight it will whine. But I'm not sure I remember correctly. Far from it in fact. :(
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Thanks Chris, you seem to be suggesting that this hum is unlikely to be coming from the diff?
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There are other possibilities. But the first and easiest thing to do would be to check the dif oil level, as you suspect. There is a guide :y
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When I had the problem with noise from the rear, even Sassenach was unable to decide if it was bearing or diff related......
What I did, eventually, as I was fed up with people hanging out of doors/windows etc etc trying to listen and pinpoint the sound was ... jack the rear of the car up and place VERY SECURELY on axle stands, with front wheels very securely chocked ... use two bottle jacks under the shock absorber lower mounts to raise the rear wheels to a more "normal" position rather than "hanging" on the drive shafts - if that makes sense.......
Start up and place in drive ... due to no load the auto box quickly ran through the gears and settled at around 20 mph, at tick over, and the noise was audible .. so under the car I went and listened ... immediately obvious it was from the diff area .. but just to be sure I pulled on each handbrake cable in turn to stop one wheel .. no change to the noise ruled out wheel bearings.
Diff was replaced with a known good used one (thanks to Rob in Bristol) and the noise just went away .. :)
Some folks have said it was reckless to go under the car with it in gear, engine running, rear wheels off the ground .. but taking a great deal of care and using some basic common sense, IMHO it was no more dangerous than being under the car dropping the diff itself ... in fact that hurt far more when it rolled off the jack and I - stupidly - tried to catch it one handed ... which was never, ever, going to work ..... :)
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I always wondered what happened to the noise to Bob Dents mv6. He thought it was dif whine, but I thought it was exhaust whistling. Tbh.
Maybe Jimbob will be along, as he owns the car now, last I heard.
Dif whine, I think 2woody said, relates to shimming of the dif. Iirc if its too tight it will whine. But I'm not sure I remember correctly. Far from it in fact. :(
Bob Swapped the Diff, and the noise changed....But it still whines.
Exhaust has been changed as well now, and the whine persists.
Its there from about 30 mph when accelerating, ease off and the noise dissapears.
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Diff whine will get better or worse when cornering, is the whine still the same when coasting down hill?, dont rule out rear wheel bearings, especially on Estates. ;)
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First thing to do,is change the oil.. And use a synthetic one to.
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Diff whine will get better or worse when cornering, is the whine still the same when coasting down hill?, dont rule out rear wheel bearings, especially on Estates. ;)
I've found diff whine is normally sensitive to load. - i.e. it might be there only under load or engine braking, but not there when coasting, or vice-versa. Sometimes, it's just always there, though.
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The hum starts at about 30mph, it is not loud at first, people who don't know what the car should sound like, have trouble hearing it. It increases in pitch and volume with acceleration. It is still present when coasting in neutral. It is no different when cornering or when accelerating rapidly (I don't normally spank her, she's getting old, but today I tried it - and she seemed to enjoy it).
The car passed its MOT yesterday and the garage say the wheel bearings are OK.
Since the sound began the rear brakes have been overhauled (new Shoes, Pads, Discs, springs, fitting kit), No change to the hum but the brake rattling and clonking has gone. Lovely.
It looks like the first step is to try a diff oil change.
The maintenance guide gives two grades of oil depending on your diff type but I understand that you can't tell what type of diff you have (LSD or not) until you take the cover off, if that is true, is there a type of oil that will suit both so I can buy it in advance?
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You can be pretty sure it's not an LSD, so any EP90 oil will be fine. :y
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Could it be a tyre related problem?
Keith B
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The diff in my 2.6 was rebuilt because the pinion bearings on the input were worn, I guess as a result of a fluid leak that was left without replacing the seal allowing the diff fluid to absorb the swarf from the bearings and become a fluid abrasive.
The noise was a metallic speed dependant noise that you just couldn't ignore!
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Could it be a tyre related problem?
Keith B
The tyres are in good condition and although they are cheap tyres there is no reason to suspect they are the cause of the noise which started suddenly, like flicking a switch. I drove two miles to drop off my daughter, on the way there was no hum, I turned around to come home and the hum began on the return journey.
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Could it be a tyre related problem?
Keith B
The tyres are in good condition and although they are cheap tyres there is no reason to suspect they are the cause of the noise which started suddenly, like flicking a switch. I drove two miles to drop off my daughter, on the way there was no hum, I turned around to come home and the hum began on the return journey.
Worth swapping the wheels front to back just to eliminate it, IMHO.
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Good idea. I'll do that.
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Whine coming from the rear? Check the obvious.
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Whine coming from the rear? Check the obvious.
If there is anything 'obvious' that has not already been mentioned in this thread please feel free to enlighten us, thanks.
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Whine coming from the rear? Check the obvious.
If there is anything 'obvious' that has not already been mentioned in this thread please feel free to enlighten us, thanks.
Wife in the back seat. ;D
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Hi Alex, I had the same problem on my last Omega and I'm sorry to say I never got to the bottom of the problem even after trying everything that has been suggested on here.
In the end I put a piece of thick foam behind the rear seat and that muffled it a bit. After that I just turned the radio up! :y
I would say live with it if you can as I spent a fair bit of money and time on it until a very nice chappie on the M56 went into the back of me doing 90mph (I was doing 70!)
He was eating a sandwich and trying to change a CD at the same time but it solved my problem!
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Been sick for a while hence the delay in reporting back.
Took the car to my friendly tyre centre to have the tyres examined and a front/rear swap.
They had a good look and pointed out that the rear tyres, although a budget brand,are practically new and that the fronts are more worn than the back with evidence of under-inflation wear to the outer edges. They said they thought it very unlikely that the rear tyres were the cause of my hum and that placing the, more worn out, front tyres on the back would probably lead to noise of its own. They were happy to swap them round for me but recommended I leave them where they are, which I did.
Looks like the oil change next. I'll report the outcome in due course just in case anyone else has a similar problem and is interested to know if it helps.
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Please do, I suspect I have a rear nearside bearing that's noisy (can't feel play - yet). It acts like a bearing ie gets noisier when turning right, and noise increases with speed, can be heard from about 40mph. It's not that loud as passengers don't notice it. But I was puzzled when someone previously mentioned (on this thread) that diff whine can get worse with corning. I've never had a rwd before so don't know much about servicing requirements of prop shaft / diff etc, so yeah please post updates :)
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Finally got round to changing the diff oil (i'm not in the best of health). When I got underneath I noticed that there is oil covering the forward end of the diff.
I assume that there is some kind of oil seal between the diff and the prop shaft and that it has failed. Still plenty of oil in the diff as is came running out when I loosened the filler plug, and it looked fairly clean. Diff is making a loud humming noise over 30 miles an hour, sound stops briefly on a left hand bend.
I am thinking of scrapping the car in view of its age and some other faults but I wonder if anyone can give me an idea of the labour costs a garage might charge to change the diff for a secondhand one (£50 to £80 on Fleabay), which presumably would also require new oil seals in the process.
Thanks for any help.
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Just read Diff Pinion Oil Seal Change in Maintenance - its beyond me I think
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Diff pinion leak is very common, and not really a problem unless it requires very frequent topping up. The seal can be changed easily enough.
Might well be worth checking the rear wheel bearings, though. Either way, not worth scrapping the car over, IMHO.
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Does a dodgy Diff Pinion Oil seal generate noise like I have described? Is it possible/likely that the diff itself is OK?
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Does a dodgy Diff Pinion Oil seal generate noise like I have described? Is it possible/likely that the diff itself is OK?
My diff was pretty messy from the moment I bought the car 4 years ago.
Back in the summer, I topped up the diff whilst I had the car jacked up to change the shocks. Actually, I topped it up with a litre of oil, so it must have been almost empty!
I hadn't considered the car to be particularly noisy before, but it was much quieter after!
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Thanks Nick, but as I've said above there's plenty of oil left in the diff and its quite clean. So, my question was, can a dodgy diff pinion oil seal generate significant noise in the cabin or is the sound most likely because the diff is also knackered?
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I had a leak from the pinion seal .. and the preload nut was not tight either ! The seal was replaced and the pre-load "guessed" at by the calibrated arm of an OOF expert (NOTE ... NOT me !!) ... a couple of years and around 25000 miles later I had a really weird "droning/scraping" noise within the cabin that steadily got worse .. initially diagnosed by another OOF expert as possibly a rear wheel bearing although it sounded "wrong" for that. Bearing changed, no change to noise.
Diff replaced with a known good used unit ... instant peace !!! and with all the gubbins off the diff you could feel the roughness by rotating the input shaft.
The only indication, initially, was an oil seep from the bearing ... :'( :'( :'(
If bored .. the saga is here ...
http://www.omegaowners.com/forum/index.php?topic=102254.0
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If the noise disappears when turning left, that would suggest a wheel bearing issue rather than a diff one :-\
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The noise doesn't start until about 33mph and there aren't many curves around here, sharp enough to remove the sound, that I can take at a high enough speed but I have noticed that in the process of taking a sharpish left curve at speed the sound stops briefly until I straighten again.
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The noise doesn't start until about 33mph and there aren't many curves around here, sharp enough to remove the sound, that I can take at a high enough speed but I have noticed that in the process of taking a sharpish left curve at speed the sound stops briefly until I straighten again.
Classic wheel bearing imho... osr would be my guess :y