Transmission / drive train noises

[rogerwt]

Hi,
My E350 CDI Sport Estate (W212) first registered March 2010 has developed two distinct noises which appear to be coming from somewhere in the drive train. One is a 'howling / whine' the other a slightly higher pitched ringing/whirring sound.
The car has done 48k miles, 28k in my ownership and has a full MB service history.
Investigations by my usual MB dealership suggested two possible reasons but could not guarantee that these were the actual causes and should I choose to have the rectifications carried out it would be entirely at my risk and cost.
The two possible causes were replace the centre prop shaft bearing at a cost of £330 or alternatively replace all the Elastomer bearings / mounts on the rear axle together with the rear nearside wheel bearing, cost £868. Again entirely at my risk and cost with no guarantee from MB that this would cure the problem.
My request for at least a contribution from MB in view of the car's relatively low mileage was refused which is disappointing to say the least especially when MB offer 100k miles within their 3 year warranty period. I accept the car is 7 years old but it has covered less than half their mileage warranty distance.
Components of this type should not, in my opinion deteriorate with age, mileage related wear maybe. This is a quality/design issue.
So the centre prop shaft bearing has been replaced at said cost and the same noises are still present and increasing.
The next step is the second suggestion, rear axle,etc, which commences this week !
If this this does not cure it MB thoughts are the differential or gearbox with associated costs that were accompanied by a short intake of breath from me and yet again no guarantee of a positive result from MB.

Has anyone experienced similar noises from their E Class and was a reason and solution found ?

From reading other comments on the forum many of you have had a similar response from MB regarding cost, contribution, guarantee, etc. Why do we keep buying these cars from manufacturers with attitudes like MB that offer poor warranties and responses to problems caused by components not fit for purpose.
This might well be my last European car having had similar experiences with Audi.
As I'm new to the forum please accept my apologies if this noise problem is an 'old cherry' however, I do recognise that the poor response from MB often is.
Regards Rogerwt

 

[Srdl]

Hi robertwt and welcome to the forum. I know my Coupe is a different platform but mine is the same age as yours and has done only 55k and, like you, I would not expect a problem at this age/mileage.

I can't help with your problem but I expect that the "experts" on this forum might like to know a bit more about when the problem occurs. Do you always have it? At any particular speed or engine rpm? Does it change with speed? More noticeable when accelerating or when engine is coasting?

 

[rogerwt]

Hi robertwt and welcome to the forum. I know my Coupe is a different platform but mine is the same age as yours and has done only 55k and, like you, I would not expect a problem at this age/mileage.

I can't help with your problem but I expect that the "experts" on this forum might like to know a bit more about when the problem occurs. Do you always have it? At any particular speed or engine rpm? Does it change with speed? More noticeable when accelerating or when engine is coasting?

Hi Srdl, thanks for your reply and interest.
The noises are always there and increase in volume as speed increases. There is a change in tone from 'drive to overrun' and my first thoughts were the differential was the cause, possibly due to a loss of preload on the pinion bearings creating backlash between the crownwheel and pinion. But of course as there are a number of u/js they could also be the cause. The difficulty is, as I'm sure you appreciate, noise travels and can therefore be hard to locate.
Driving at a constant speed I've tried going through the gears using the paddles in an effort to see if it was more gearbox related but there was no distinct change in noise level or tone.
Cornering, left or right, straight line makes no difference, it's the same.

Regards Rogerwt

 

[LostKiwi]

Your description does suggest the rear differential or possibly a wheel bearing.
A UJ or CV is very unlikely to make a whining noise - they usually make much more of a grinding or squeaking noise if they make any noise at all.

Rather than get MB to look (they tend to be module swappers and not fix anything and charge extortionate hourly rates for the privilege) use a good independent if there is one near you. Where are you located? We can probably recommend a few good places to go.

 

[rogerwt]

Your description does suggest the rear differential or possibly a wheel bearing.
A UJ or CV is very unlikely to make a whining noise - they usually make much more of a grinding or squeaking noise if they make any noise at all.

Rather than get MB to look (they tend to be module swappers and not fix anything and charge extortionate hourly rates for the privilege) use a good independent if there is one near you. Where are you located? We can probably recommend a few good places to go.

Hi,
I live near Newport, Shropshire. I did contact a company in Telford called AutoTech who were highly recommended by a couple of chums who use them for various high end Mercs, Jaguars and BMWs asking for a quote to replace the centre prop shaft bearing but they never replied. As I thought they weren't interested I didn't chase them and went back to MB where I am now committed to them carrying out the next step on the rear axle.

 

[John Laidlaw]

As LK says, sounds diff/bearing related but without proper diagnostics ....if you're commited to MB anyway you'll have to stay on that gravy train until they swop out modules/parts etc....eventually they'll find the right one I guess.
Main MB dealers generally act this way as the majority of their work is warranty/less than 3YO cars often on lease these days, so it becomes a habit. That's my experience anyway...

 

[Arudge]

Bearings tend to make more of a rumble or drone. When there wear they can simply wear out and stay silent but go sloppy, or the bearing track starts to break up leaving pit marks in the track. The rumble or drone is the noise of the ball bearing passing over the pits, the bigger the pits the deeper and louder the drone.

Bearings are mass produced, not particularly accurate and if their a tad on the tight side when assembled the heat generated will destroy the track surface, the surface will 'pluck' and generate the noise.

Bearings come in lots of different tolerances, the high speed bearings we use are stupidly expensive and have strict running in procedures, you don't find them on cars!

Whining noises are usually gear related. Usually that the meshing surfaces are incorrectly aligned, sitting too deeply in the mesh, incorrect or worn contact area or insufficient preload. There are distinctive pointers to what's making what noise inside a diff but I'm too many years away from when I studied the theory!!

And no, none of this can be diagnosed by STAR, so the boys at MB are going to be stuffed!

Differentials have to be 'setup' in manufacture, get it wrong or you lose the lubricating oil and you end up with noise. As always, heat is the enemy.

Given your description, your simple but effective testing procedure, I'd target the differential, buts that's only my opinion, but they they are quite a piece of work and there's a bit more going on in there than some would realise.

 

[charlysays]

When I first got my first C250 TD I was alarmed by 1. The whirring noise as the engine revs climbed, which sounds a bit like a howl and is most audible below 2.5k rpm and has been there on all OM605 TD engines I've come across. Even with viscous fan removed it still did it! 2. The whine from the transmissions most noticeably on the overrun / engine braking in 1st and 2nd- really quite noisy. They also make a kind of spooling up noise as you take off in 1st gear though this may not be the trans. The engine braking noises are definitely transmission related.
We've got four of them with mileages ranging from 65k miles (on a T plate) up to 250k miles (S Plate) and they all do it. Could be you have very good hearing like me or are MB agreeing with you that the noise shouldn't be there?

 

[Arudge]

Just re reading your original post, I can't understand why MB should conclude that a noise clearly linked to rotary movement can originate from a static bush? I think your own conclusions are more accurate, I'd stop your last instruction if there's time.

As charlysays pointed out, some noises are simply caricaturistic of a certain make, model or component, such as turbochargers and superchargers. The older of us will remember the transfer gear whine of the old mini's, a rubbish design that nobody was ever going to do anything about.

But this is Mercedes, and we expect better.

I'd also dismiss the CV and UJ joints for the reason Lost kiwi suggested. Although these parts spin a considerable speed they don't actually move much, fractions of a mm, so your not going to experience whine or howl from there.

 

[Srdl]

When I first got my first C250 TD I was alarmed by 1. The whirring noise as the engine revs climbed, which sounds a bit like a howl and is most audible below 2.5k rpm and has been there on all OM605 TD engines I've come across

The OP has a V6 engine.

I think your own conclusions are more accurate, I'd stop your last instruction if there's time.

I tend to agree. Time to let a good Merc Indie have a listen to the problem.

 

[steveq]

Hi,

I'm sure you have gone through the "when did it start and was anything changed just before it started" question? Maybe even changing tyres might have affected or damaged something?

Also, I suggest that the auto transmission oil and filter are changed and the back axle oil is changed. Both are cheap compared to your options above and, given the age of the car, are worthwhile anyway.

Best of luck with it.

 

[rogerwt]

Hi,

I'm sure you have gone through the "when did it start and was anything changed just before it started" question? Maybe even changing tyres might have affected or damaged something?

Also, I suggest that the auto transmission oil and filter are changed and the back axle oil is changed. Both are cheap compared to your options above and, given the age of the car, are worthwhile anyway.

Best of luck with it.

I've had the car for about 4.5 years and before these noises started it was, as you'd expect extremely quiet until about 3 months ago with nothing being done to the car immediately prior to that.
Thanks for the suggestion on oil and filter changes, I think that is a sound idea which I'll get sorted.

Thanks to you and all others for your comments, much appreciated.

 

[John Laidlaw]

If it wasn't for the whine I'd be thinking tyres....

 

[Arudge]

If it wasn't for the whine I'd be thinking tyres....

Tyres can certainly grossly increase cabin noise, 4x4 owners choosing chunky block tread tyres tend to end up wearing ear defenders.

I can't stand cabin noise so a tyres db rating is always high on my list.

 

[LostKiwi]

Tyres can certainly grossly increase cabin noise, 4x4 owners choosing chunky block tread tyres tend to end up wearing ear defenders.

I can't stand cabin noise so a tyres db rating is always high on my list.

The noisiest tyres I've ever had (and that includes a lot of 4x4 ones) were some cheap horrible chinese 235/35 R19 ones that came on my r129. Dreadful things. Put them on the S210 just to try and wear them out but they wouldn't so they had to come off again.

 

[kid-jensen]

My vote goes for the diff for the whining, and maybe the transmission for the high-pitched ringing/wirring (but that could be an engine accessory).

Changing oil is always a good idea, but in my experience, rarely quietens noises down once they've started..

 

[charlysays]

Second that on tyres, they can make whining and droning noises in my experience.
When I noticed whining (from a different model engine) as well as noise from my 722.6 gearbox my solution was to turn up the stereo, after checking that all systems had the right amount of fresh fluid etc!
Let it develop, it'll be easier to pinpoint.

 

[rogerwt]

So here is the next episode on the above.

I've been over to MB this afternoon to inspect the removed rear axle assemble with the following outcome.

The good news is that both rear wheel bearings are fine, no need for replacement and not the cause of the problem.

The differential was on the bench and stripped but with the pinion still left in place. Rotating the pinion explained the cause of the noise. You'd have thought there were square rollers in one or both of the taper roller bearings. Very lumpy / notchy, ie knackered and clearly the cause!
The solution is a replacement differential with unfortunately still no contribution confirmed from MB, a simple flat refusal. Apparently even after them talking to a real person at MB UK rather than just accepting the answer provided by their computer based request system.

So the 'go ahead' has been given to replace the diff along with the axle assembly support bushes which seems sensible considering the age of car and the cost of labour to remove and replace the assembly should these be left to a later date.
By the time this job is completed there might be enough change from £3k for a round of drinks ! Ouch.

To say the total failure of the differential after 48k miles is disappointing is an understatement, not acceptable on any vehicle really, but definitely not on a car of this claimed quality and cost. You, not unreasonably, expect better.

Apparently a search of the service history on the car did not reveal any historical references or reports of issues associated with the drive train and we saw no visual evidence of earlier 'work' being carried by MB or others when examining all the components. Particularly the differential itself, not even an oil seal replacement, which I was told is sometimes required on this model. No sign of a leak, externally as dry as the proverbial bone, so loss of oil was not the cause of failure.

The replacement is 5 to 10 working days away so hopefully the car will be back and cured by the end of the month, without of course any guarantee from MB regarding 'a cure' but thankfully I think this will provide a successful resolution !

Obviously I'm not satisfied with MB's response and as far as I'm concerned the matter is not closed.

Thanks for all your comments, they're very much appreciated, I'll keep you updated on any developments and outcome.

Regards Rogerwt

 

[LostKiwi]

Sadly you just got shafted by the MB replace it all mentality instead of the indy fix it mentality.
Bearings can almost always be replaced at a significantly lower cost than replacing the entire differential.
A typical price for a full set of diff bearings would likely be under £150.

 

[Arudge]

Sadly you just got shafted by the MB replace it all mentality instead of the indy fix it mentality.
Bearings can almost always be replaced at a significantly lower cost than replacing the entire differential.
A typical price for a full set of diff bearings would likely be under £150.

I'll second that.

This is most frustrating as all bearings have bearing numbers clearly etched into them, SO YOU CAN REPLACE THEM!!!

Diffs are designed to be rebuilt, there is no need to replace.

At least you've seen it with your own eyes and now accept that bearing failure is not restricted to lesser marques.

Yes we expect more, clearly we're not always going to get it.

If at all possible, could you post images of the damage? I'd quite happily pay for the carriage so I could open the bearings up and document the damage to the tracks.