kricoperry

Hi,

I see from doing a number of seaches on vibration that there are many, many posts relating to driveline vibration but it largely seems to be a hit and miss diagnosis exercise, often with many parts replaced and no full solution.

My car has a vibration or thrumming, drumming noise starting at about 120 km/hr and up, not heavy, but very noticeable and annoying. It sounds that it is a higher frequency than from the wheels or axle shafts.

I had the driveshaft balanced, new centre support bearing and mount, and driveshaft bushings done but no difference. The flex disks were apparently OK.

I think the possible causes could include:
1. driveshaft bent or unbalanced (already balanced)
2. flex disks damaged
3. U-joint wear
4. worn centre support bearing or rubber mount (replaced)
5. driveshaft angular misalignment (transmission/front shaft ;front shaft/rear shaft; rear shaft/differential)
6. loose or worn differential mounts

Does anyone have any advice to narrow down the possible causes? Does anyone have a copy of the MB TSB on driveline vibrations that recommends addition of a damper on the differential?

I was thinking of tape recording the sound inside the car and putting it on an oscilloscope to look at the relative frequencies. One can easily calculate the driveshaft RPM vs road speed, but there may be other multiples as well, eg: 2x per rev, 3x per rev, 6x rev, based on physical geometry of flex disks and fastenings.

Any advice or experience troubleshooting and what actually worked to cure the problem(s) would be very helpful.

Very best regards,

James
Toronto, Canada

RogerJones

Copied from my own post in another thread, in case you haven't seen it:

"From the E-Class Owner's Bible (Bentley Publishers, ISBN 0-8376-0230-0), which heads the problem "All E-Class":

"Driveshaft out of balance . . . if problem persists, install rear differential vibration damper, MB part no. 124 350 03 72 at rear subframe. Tightening torque 150 Nm (110 ft-lb)."

My Coupé's driveshaft was not out of balance (my mechanic reckons that it is so distinctively harsh as to be immediately recognizable) but there was what the Bible calls "a thrumming" in this speed range. I've had the damper fitted: a very heavy item that just slots in easily. It has severely suppressed, but not completely eliminated, the thrumming, but it is no longer a source of annoyance. I have not detected the problem in my turbo sedan."

kricoperry

Thanks Roger. I had seen this from you before. When I called MB (one of the dealers in Toronto, Canada) about this part # the parts tech said they had no record of it and had never heard of such a part as a vibration damper that bolts on to the differential. Any ideas on how I mht locate one?

Regards,

James

RogerJones

I would go back to that dealer and ask why, if the part is numbered on the MB system and you know that someone else purchased it on 16 September 2006 for £105.43, they cannot facilitate the same transaction. Furthermore, I obtained the information from a US publication, so it's not as if the distribution of the part is confined to obscure outlets in Europe -- the MB system is worldwide, after all. Don't think about mail order, as it weighs a lot. Suggest that the dealer contact the parts advice desk first at MB Canada and then, if necessary, in Sindelfingen. It may be that it is not stocked "locally", but it exists and can be supplied.

kricoperry

Thanks very much Roger. I will ask MB.

Regards,

James

RogerJones

I have some new vibration and my mechanic is going to replace the propshaft bearing mount. It's 11 years old and contains some soft bits; the vibration comes on with power on and diminishes when off; hence, it's worth a shot. Not expensive (USD 25 from Euro Car Parts, OEM spec), although it will take a couple of hours to replace, as I understand that the exhaust has to come off.

Yura_Coupe

Hi!
Maybe it is funny, but try to balance your wheels.
I have the same problem, but can't call the cause of the vibration, because few days ago i had changed tyres into winter ones, they had been balanced, and i had not tried to drive above 110 km per h

Best Regards from Ukraine!

AMGDave

Here's the factory docs for the dampers:

http://www.w124performance.com/docs/...s_early124.pdf

http://www.w124performance.com/docs/...es_late124.pdf

jlink38

Also, make sure your wheels are not bent, and the tires are fresh, as my rear tires are starting to wear and the previous owner did not ever rotate them and they are starting to feather. Also, one of my rear rims is bent and that is causing most of the vibes at highway speed.

Brian McL

I have the same drumbing in my 400E. Can't find a smokin' gun anywhere. I have disengaged the rear 1/2 shafts so the engine isn't driving the wheels and it is still there. New hanger bearing...still there. Swapped thefront and rear flex disc ('cause they are OK) still there. How could the driveshaft suddenly become unbalanced. The original weights are all in place and the shaft itself looks like new. The thumping is definitely in the rear..I can feel it with my hand on the diff. This is BS. Could there be something inside the differetial that needs to be balanced?? The vibration damper mentioned above doesn't apply to the 400E / 500E (124.034 /124.036). I think I am going to push this one down the road......enough already!!

AMGDave

If the driveshaft halves were ever separated, make sure they are put back together correctly - there are marking on each half that need to match up. The second link above does mentioned the 124.036, but I don't know if that is a typo or not. Measure the distance between mounting bolts on your 300E compared to the 400E, if they are the same, then the damper may fit the 400E also. You could also check/replace the differential mounts as well... there are two (horizontal) in the front/top, and two in the rear (vertical). Here's photos from a 185mm diff, but the 210mm should be similar:

Brian McL

It must be a typo...I don't think the 500E was out then. Anyway, I have another driveshaft complete that I am goingto put in now. I sure hope this solves the vibration.

Brian McL

.....and how do you balance the DS in the car? as mentioned in the .pdf link above.

Brian McL

OK...so replacing the DS made NO DIFFERENCE.....so it can only be in the differential. That will be removed this PM

MBNUT1

I had a similar problem with a 190E that I tried everuthing to solve it short of replacing the differential, which I had a mechanic tell me that he had replaced more that one for wear issues.

Brian McL

Diff was out...opened...looked at and no apparent problem. Everything looked fine. No bearing wear...no broken teeth...nothing. Time to sell it !!

AMGDave

how about trying a used differential? They're not that expensive. Also, it could be an alignment issue with the differential to the subframe... I think there are shims on the front/top mount. Also, if the flex discs are old, it wouldn't hurt to replace them. Rubber hardens with age. If you like the car, I'd sure give it a try before giving up & selling it...

Brian McL

Well....many months later with still no explanation. Tried selling the lemon but the vibration is quite noticeable. Yesterday I took a wheel weight and clamped it to the DS near the diff....reduced the vibration alot, but not completely. But good enough to sell...I hope. What a dog!!!!

murky damo

Hello, sorry for the long post...

I drive a 1990 260E, it only has 130km but it is getting a little old and tired. The problem is similar to kricoperry, but I have a wobble coming from my rear end at pretty much all speeds. It feels as though something is a little loose, even at slow speeds it seems to be moving, or wobbling a little from side to side. It is not major, but it is defiantly annoying!!

My brother is a diesel mechanic, and he had a quick look previously and saw the gear box to drive line coupling/ flange was quite loose, and we replaced it. That helped quite a bit, but we pretty much stopped looking once we found the worn coupling hoping the problem would be as easy to fix as that. Since then the problem has not gone away, and I haven't been able to convince him to have another look yet.

The mechanics I have seen recently have pretty much said leave it until it gets worse or just ignore it, but it is driving me mad! My mechanic has also mentioned he thinks the drive line needs to be balanced. (He has specialized in Mercs for 25 years, but more the older more basic models which he can do out of his back yard with out diagnostics, he is old school)

I have also been to my tyre guy, and he thinks it is mechanical too, i.e.. not tyres or suspension.

Has anyone had the experience of the driveline being unbalanced? Is this a common problem, and is there a way we can check this first without sending it off to be balanced and having the car off the road for a few days needlessly?

To save some cash on getting any work done, I'm trying to get my brother to do most of the mechanical work, but identifying the problem could potentially be a little harder, and I don't want to waste too much of his time. I was wondering if anyone has had a similar problem, or any insights as to a couple of the more common problems that could be causing this, and what to signs to look out for, etc. Any ideas would be much appreciated.

I have also seen from this thread the mention of "rear differential vibration damper". Does this essentially hide the problem? Would I be better off trying to get the driveline balanced, or as a potential cheap fix try the vibration damper first, or is this predominantly for the high speed vibration issue?

Cheers Guys.

six-wheeler

Hello everyone,

I've been battling the exact same issue as the OP's with the exact same car as the OP\s (a 1994 E320) with the exact same symptoms, for more than a year. At some point, I couldn't even drive the car beyond about 110 km/h because the vibration was utterly unbearable. But I - or, rather, one of my mechanics - finally found the problem: a compressed transmission mount.

As usual, I replaced almost everything: drive shaft doughnut couplings, center bushings, center mount and bearing, both rear differential mounts (but not the front mount - yet), engine mounts, and even the tensioner, idler and fan pulleys on the engine!

I had the drive shaft checked for balance twice, and it passed with flying colors. I even considered replacing it just to be sure, but yesterday, the mechanic confirmed what I had been suspecting all along: the driveline was out of linearity, i.e. the transmission was sitting a little too low, and hence the drive shaft was spinning at a slight angle at the front doughnut coupling - which places too much stress on the the center bushing to keep the drive shaft centered.

So, this morning, we took out the old transmission mount and compared it to a new one I just bought, and there was a difference of about 7mm in height. We put the new one in and voila! No more vibration - almost! I still might need to place a washer between the transmission's tongue and the mount to tune out the slight residual vibration that's still there, which I'm planning to do after the new mount has been broken in and settled, but still, it's a world of difference!

Bleu62

I've seen a few different models on this tread so I think I'm ok to ask this. I'm having very similar symptoms as the OP, rather the vibration is at very low speeds in first gear, or in lower rpm's in second. And abruptly smooths out around 25 mph, while keeping the rpm's up. Otherwise the vibration stays until enough torque is applied. Anyone dealt w this before?

Plutoe

I can't add much except that 124 350 03 72 must have been a differential repair kit as it is no longer available in kit form----group 421 is drive shaft; group 350 is differential.

Regarding vibration, all I can add is put on a lift and carefully watch all rotating surfaces!!

six-wheeler

From my experience, what you're describing is usually caused by a bad or severely aged transmission mount. It's a relatively easy DIY replacement and the part isn't very expensive (especially from brands like Lemforder; the part is far cheaper than OE and about as good.) I would suggest you address that - which you should anyway, given the car's age - and report back here with the results.

Bleu62

Thanks plutoe and six wheeler. 6wheeler-I'm going to check that ASAP and let you know. Crossing my fingers it'll be that easy

six-wheeler

By the way, I should update you all on how the situation turned out after I made that last (and my first) post on 25 September. To make a long story short, my cousin, who is a veteran, MB dealer-trained mechanic/technician in Amman, Jordan, worked on the car from bumper to bumper, and finally traced it all down to three issues: a bent driveshaft, a bad transmission main shaft, and a bad tire, all of which had since been sorted out, and now the car rides and drives like a dream. You can find the entire details here. (I'm sorry for the redirection to another community altogether, but it saves me the effort of writing it all up again.)