I have a bad vibration which sets in under throttle at around 75mph. It disappears when I back off the throttle. I have just bought the car and the previous owner has a receipt for a part called "propshaft coupling kit", and I am not sure whether it was the back or front!

This vibration is felt throughout the car at speed, there is an annoying droning noise as well as a feeling coming through the seats and steering, all the wheels have been balanced.

I jacked up the rear of the car at one side and there is a fair amount of freeplay/slap at the rear diff when you rotate one rear wheel with the other on the ground. I am sure the rear diff also make a slight whining noise at low speed, almost like a failed wheel bearing.

The rear flex disk looks in good condition.

With the transmission in park and rotating the jacked up rear wheel I can see the propshaft rotating at the large circular vibration damper behind the transmission flange, but there seems to be quite a lot of freeplay between this and the flex disk attached to the transmission flange. I take it that this means that the front flex disk worn out as I suspect there should be no play. There is also a sligh rubber squeaking sound like a mouse from aroung this area. My friend's 190e has no play at this point. Will replacing this front flex disk cure my vibration problem??

Thanks in advance for your help.

Doug
London UK

Thanks for your help

Doug
That's where I would start - it may very well cure the vibration problem.
Good luck, Bruno

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1992 300TE 160 kmiles

Do I need to take the transmission support bar off to change the front flex disk or can it be done without.

Do I need to remove the exhaust heat shield and loosen the sleeve nut to allow the splined section to slide back?? My haynes manual isn't very clear on this!

Thanks for your help!

can anyone else shed some light?

Ok, since nobody else answers I'll give it a try. I recently changed the transmission mount, the rear flex disc and the support bearing of the driveshaft on my W124. Based on this experience I'll say that you do not need to remove the transmission support bar but you need to collapse the driveshaft by loosening the big sleeve nut (and unboltung the driveshaft boot). In my case the flex disc was almost baked to the driveshaft and was hard to separate. Sensible use of an air chisel came very handy at this place.
Good luck, Bruno

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1992 300TE 160 kmiles

Have just seen your e-mails as I am about to replace the vibration damper on my C180. If you have replaced your's yet I guess you found that removing the cross member gave better access. I believe the sliding joint allows the front propshaft to be moved back. Is this correct? Did you find that the vibration damper could be easily removed once the bolts were removed. My flexible coupling looks OK so I plan just to remove the damper. I believe the centre of the propshaft only needs to be disturbed if the rear flex coupling is to be replaced. I would be grateful for any advice.