My 240D vibrates at certain revs when in drive. It seems to vibrate more under acceleration and at certain revs, not speeds.

The driveshaft support rubber where the spline joins the next part of the "propellor shaft" (as the germans like to call it) about half way between the differential and the transmission, is cracked and I can push the driveshaft a good 1/2 inch up and down in the supports, ie the driveshaft doesn't seem to be securely held in the supports and looks like it could wobble or 'orbit' in the supports. However, I find it hard to believe that those little rubber supports (kinda like a CV boot) could hold the driveshaft in place at high revs.

Is it the center bearing (pic attached or see at http://www.partsamerica.com/ProductDetail.aspx?mfrcode=BCA&mfrpartnumber=106&parttype=907&ptset=A) that holds the shaft in place?

I am assuming this driveshaft movement is bad, but am not sure, since I haven't seen any to compare it with.

If this is bad (the drive shaft moving 1/2" in the supports) then how do I fix it? Replace the driveshaft supports? Replace the drive shaft center bearing?

I have read various posts on this and looked at the MB shop manual (see http://skinnerbox.steaky.org/Service/W123/w123CD2/Program/Chassis/41-200.pdf ), but am confused as to what to replace, and more importantly, what it is called and where to buy it from. There are a few places on the web to buy parts called Driveshaft center support bearing (pic attached), or driveshaft support bearing, driveshaft support or driveshaft centerbearing.

HELP! confused! And want to fix it! Also, might it be the flexplate? How would I tell?

Thanks, and help would be greatly appreciated. I've worked on a lot of car things, but never a drive shaft! Feeling intimidated!

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Half an inch deflection is too much. Year, that rubber really does help hold the center of the driveshaft . I would replace both the center bearing ( you have the picture) and the rubber mount (center support) that it fits into. Both together should run you no more than $30 on fastlane. I have done 3 of these and have the actual replacement of these bits down to 10 minutes. Be sure to mark the orientation of the rubber mount. If you haven't done the flex discs recently, this is a perfect opportunity to do them as well. Especially good to do this if you have a manual transmission where new rubber helps absorb some of the shock to the rear end and driveshaft.

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Awesome, thanks for that reply! I feel like I can handle it now.

Sounds like I should replace the flex disc, center bearing and drive shaft support.

Then what's all that stuff in the MB Manual (see the pdf link from my previous post) about drilling holes and pulling things out?

Thanks for your help. Much appreciated, also the heads up on fastlane.

Paul

Paul,
Don't worry about all the hole drilling. That is for something else. All you have to do is mark the shaft before you separate it and check the condition of the u joint while the front section is off. The joint should move smoothly through all range of motion without any roughness except at the straight up position. Roughness passing through center is permissable on a shaft that has been in service for quite awhile.

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Thanks AutoZen.

Sounds pretty straight forward. I ordered a bearing and support and a flex disc (may as well while I'm at it). I'm sure I'll know what the U joint is when I see it.

Looking forward to less vibes from my baby!

The u joint is what you are going to slide the new bearing up to.

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