w211 7gtronic PERIODICAL vibration possible TC failure

[Andreyy]

Hello friends w211 320cdi.I have a issue with vibration on high speeds. At first,i think,that it may be the wheels,tires,but when I changed to the winter,its no change.. Problem looks like,when the speed is over 140 kmh on highway(for example,I go 150kmh with cruise turned on) The car starts PERIODICALY vibration on the body,the increase in vibration begins to grow,after 3 seconds it reaches top level,then about 3 seconds gently goes down,and for about 3 seconds car goes very smoth(no any vibration) ant then againt start to raise....and it happen all the time No deppends winter tires or summer,but logicaly tires,whels vibrate always,they cant some time vibrate,some time no..flex disc i think also vibrate or no.. But my issue is vibration at the same speed,which goes up and down all the way.. Also,I searched some info about the TC issues on 7gtronic,and I found,that TC can vibrate in low rpm and high loads(ex 60 kmh going uphill on low rpm) that symptom i have to,slight vibration on high loads and low rpms..also when going 80-90kmh at low rpm and start acelerate(high load,ex uphill) I also feel slight vibration. Maybe anyone can help with my issue?Maybe fluid level is so low? Or here is TC failure.. Thanks

 

[Larkone]

Or engine mounts or gearbox mounts or prop bearings

 

[Andreyy]

Realy can engine,gearbox mounts give the periodical vibration,which reapets like a song..(3seconds vibrate,3seconds gone..at the same speed and load with cruise control) hmm At iddle here is no vibration,like a common symptom with bad engine mounts..

 

[Andreyy]

Of course,when CV joints a bad,common symptom,car vibrate under load,more load,more vibration..drive shaft bearing common symtom on rwd cars(like bmw or merc) vibrates under load at specific speed range(dont know mb,but bmw is 30-60kmw under aceleration) My situation,here is no load(can go with cruise control downhill) at speed,over 140 kmh,and no depending,its 143 150 160 or more..I can cruise 160,then vibration has the same periodical moment(3sec vibrate,3sec no..),but at higher speed(example cruise at 160 on highway) vibration feels stronger.

 

[mattkh]

Where exactly do you feel the vibration?

 

[pgh13]

Usual questions.... What mileage and how long since transmission service?

 

[Larkone]

Realy can engine,gearbox mounts give the periodical vibration,which reapets like a song..(3seconds vibrate,3seconds gone..at the same speed and load with cruise control) hmm At iddle here is no vibration,like a common symptom with bad engine mounts..

But they are easy to check at no cost before you start throwing money at the expensive options.

 

[Doug1234]

Does it only do it when using cruise control ?.
I wonder if the cruise control is applying throttle and letting off and applying again, it seems the only logical thing to me that could be making vibration come and go every three seconds like it is.

 

[Andreyy]

Does it only do it when using cruise control ?.
I wonder if the cruise control is applying throttle and letting off and applying again, it seems the only logical thing to me that could be making vibration come and go every three seconds like it is.

No,it does in always This is example I can go without cruise control,at the same speed,and keep preesing throttle ant the same place,(no leeting off and aplplying againt,like sometimes cruise control does it,because off uphill or downhill) No matter cruise on,or going without cruise,symptoms is exactly the same.

 

[Andreyy]

But they are easy to check at no cost before you start throwing money at the expensive options.

Yes,I aggre to But in my experience,flex discks,driveshaft bearing vibrates all the time on common speed or load(not periodical..appears and disappears) wheels vibrate all the time,where vibration depends on speed. Mounts usually vibrates on idle,on R or D.Gearbox and engine mounts cheked No vibration on R or D,no vibration at idle(common symptom of bad mounts) Cheked a rear flex disc(guibo). Its not broken,but small intrusions are visible..front flex disc in good condition. How i can check a rear CV joints? I have expereince in BMW(E60)where driveshaft to diferential connected with CJ joint(in w211 its connected with flex disk)..and in this bmw was a very high vibration, it seemed that all the screws and the machine were loosening immediately here it is difficult to put into words..here vibration depends on load..a little throttle(and no matter of vechile speed) and car starts to vibrate..and a load sound comes like a wouh wouh..some mechanics try to find the problem,and no luck..then i found in forums,that it can be a driveshaft CV joint,especially if you see leaking grease,then a CV joint work in dry conditions.. And after this post,when I with my friend start to replace it,we try to check the driveshaft to lossenes in rear CV joint,and when we tried to move the shaft,here is no lossenes(maybe a little,like a 1milimmeter,when we compare with old) BUT inside CV joint,where is the metal balls,places,where they should be,was a 2x bigger..just a little bit more,and 2 balls could fit in one place.. How i can check the rear CV joints? Its difficult to identify.. And,maybe with a STAR is possible to off the TC lock up on 7gtronic? If its possible,I think,that then,if vibration goes out,its 100% TC..if no,problem somwhere else. Sry for my bad english and thanks for replies

 

[Andreyy]

Where exactly do you feel the vibration?

Its difficulty to say..on all car,its like a going with unbalanced or with curved rims rear rims

 

[Andreyy]

Usual questions.... What mileage and how long since transmission service?

I Bought a car a half year ago,millegae is 300 000kilometers,transmission not serveced,only ckeked fluid level..I have to done 3-4k kilometers to the next engine oil change,and then together I service a gearbox

 

[mattkh]

Its difficulty to say..on all car,its like a going with unbalanced or with curved rims rear rims

OK. With unbalanced wheel, I feel the vibration on the steering wheel.
Are you feeling any vibration on the pedals?

 

[Andreyy]

OK. With unbalanced wheel, I feel the vibration on the steering wheel.
Are you feeling any vibration on the pedals?

On steering wheel no vibration-shake,like with unbalanced wheels..On pedals no,vibration feels on car body..like a drivetrain problem..or like a bad rear rims..they also feels on highway speeds,and sometimes dificult to say,that vibration realy goes from rear

 

[mattkh]

Thanks.
Tell me as much as you can about the tyres.

 

[Andreyy]

Thanks.
Tell me as much as you can about the tyres.

Summer a pirreli,winter(now) Nokian. All tires have size 240/40r18.. But my rear rims need to be fitted with 275/35,because rims a wider. But I dont think,that here a problem..the same with winter tires and with summer tires,rims smooth,perfect condition At first time at the summer,i also think,that i have a rear rims or tires issue..But then I noticed,that car vibrates not all the time,its periodical..gently starts,reaches the peak,vibrate some seconds,then gone away..then again and again..after that i realized that the rims cant do this..and after tires swap to the winter,its exactly the same..and I realized,that rims and tires a 100% perfect..

 

[Andreyy]

Can on this models with star turn off the torque conventer lock up clutch? If yes,then I think I start from here,try to go on highway,and with star turn off the TC..if vibration gone,then TC needs to be replaced,if no,then try to check again all drivetrain(if my vibration wasnt periodical,of course,I would start it from driveshaft,wheels,CV joint,center bearing,flex disks..) but here its feels like a magic,come an go out,come and go out...I can go 100kilometers,from city to city,and all the way its do the same..

 

[mattkh]

Thank you.
I do not know anything about automatic gearbox. When you changed to winter tyres, did you test for any play in the wheel bearings.

 

[Andreyy]

UPDATE. I had a small crash to the rear left side,and my rear subframe a broke. After crash I change the rear subframe,and change all 4 rear subframe mount to the new(my rear subframe fron mounts was worn,had some not big interuptions) And after rear subframe change with new mounts now no periodical shakings-vibrations,run smoth(only after 150kmh have some vibration,but not periodical,its like rim tire shake) After that I call to 1 mers service and told about my problem,and after what repairs problem disappeared and they say,that yes,if rear subframe mounts a bad,then car can shake on speeds,depending on road conditions..sometimes can shake sometimes no. If anyone have shakings like a bent rim on high speeds,look at the rear subframe mounts,it can bee issue Shakings can change,depending on road conditions,one time at the same speed so strong,second time so smooth.

 

[mattkh]

Thanks for the update.