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W203 drive line vibration

Tim203

Active Member
Joined
Sep 17, 2014
Messages
399
Hi, after an indie visit to disable the lock up clutch on the converter confirming the vibration went away, they and myself were not entirely convinced that was the true problem. I bought the cd220 a year ago and on test driving initially detecting a very faint vibration from the prop tunnel area when under load in higher gears. I changed the centre bearing straight away and it didn't cure it hence the visit to the indie garage. I have since put the correct oil in and filter changed and didn't change anything. It is rpm related, 1800 to 2200 rpm generally in bigger gears. Tipping down a gear normally gets rid of it presumably reducing the torque loading.
What I think re awoke my thoughts about this annoying car was a comment on the forum last week or so on engine mounts. Referring to switching the engine off it does stop with a thud for want of a better word and I noticed this when I purchased it but dismissed it as quirk that Benz's had being an inline engine.When the problem occurs during accelerating in probably 3 rd gear upwards it starts with a bumpy sensation as if the wheels are out of round and starts a resonance down through the tunnel ( if you don't back off or knock it down a cog) until the heat shields in the tunnel start vibrating towards the rear. I can liken it to my dog shaking himself when he gets out of the water. I put the car on the lift again this morning to inspect the engine mounts and gearbox's at the back, and all appeared to be ok. This doesn't mean that they are of course! Visual is tricky on the offside engine mount but I lifted the mount with a bottle jack and the engine didn't lift much before rocking the car on the two poster lift! The U.J on the prop is tight and both rubber flex joints apart from surface perishing appear to be in good order. Diff mounts are solid and diff has normal amount of backlash. The only play I can detect is in the splined shaft connecting the prop shaft sections. I've kind of ruled out prop shaft problems as it is very much engine rpm related and not road speed. The car has just had 4 tyres and a new ticket. Advisory on slight play in rear anti roll bar rubbers and failed on offside front spring broken. That's quality for you! Or rather not. Whilst on the subject you'll need a helpful garage to compress the spring on a hydraulic rig if your doing this yourself as there is no access on standard spring compressors ( spring being smaller than the seats) and not enough coils to hook onto. The car now has 137k miles on it and this vibration and or lockup clutch slip ( if it is that) spoils the car completely. If anyone out there has a similar experience to me it or knows of a fix ( apart from burning!) I would be pleased to here from you . I hate to say it but my old 406 that we've had from new in the family has another 100k on top of this car and has a lot better record on having bits replaced despite Top Gears opinion :)
 
I'd get a second opinion.

Did the vibration go after the lock up clutch was turned off?
 
Apparently so but I wasn't there to witness it! Logically speaking it would soften any drive line by decoupling a direct drive from the engine . Last oil change ( trans.) in the service book was with ATF 28 which I have no idea if it was unsuitable, the oil lab report showed higher than than normal copper particles but little sodium ruling out the glycol inclusion from the radiator heat exchanger . The transmission works perfectly apart from that. Thanks a lot for your input.
 
Tim203 said:
Apparently so but I wasn't there to witness it! Logically speaking it would soften any drive line by decoupling a direct drive from the engine . Last oil change ( trans.) in the service book was with ATF 28 which I have no idea if it was unsuitable, the oil lab report showed higher than than normal copper particles but little sodium ruling out the glycol inclusion from the radiator heat exchanger . The transmission works perfectly apart from that. Thanks a lot for your input.

Engine mounts are fluid filled. They leak a brown rusty/black liquid when knackered.
At 100k+ I would expect them to be worn out.
Get an experienced MB tech to sit in it at idle. It's that obvious. I will do it for no charge if it helps?
 
Thanks for your advice, no sign of anything oozing out, I have noticed symptoms are worse after sat in traffic .Either the turbo/ cat is warming the offside mount up or the transmission fluid is getting hot! I must have a look and find out how these mounts function. Tickover feels fairly normal however I have nothing to compare with but switching off is quit shaky but something has to give, these Avantgarde set ups are very strongly sprung. I am curious about the 100k lifespan and these mounts don't look as if the've had any tools near them.
 

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