In an effort to determine why I (and others that have done this installation) have a driveline vibration after installing manual trannies in my car, I am conducting a research mission and have a request:

If you have a Euro (gray market) 115, 123 or 126 chassis with 616 or 617 engine and a manual transmission and, could snap some photos of the driveline, I would be much obliged.

Photos of the front flex disk, rear transmission mount, and rear flex disk would be greatly appeciated.

When you post pics, be sure and tell us the chassis model, engine type, and year.


Thanks!!!
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Never a dull moment at Berry Hill Farm.

Ok... my MISTAKE

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Thank you.

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Never a dull moment at Berry Hill Farm.

Leo,

I replaced the driveshaft in my Euro 123 with one from a US 123 and could see NO difference whatsoever between the Euro and US.

To troubleshoot your driveshaft vibration, however, I would start by ensuring that the front and rear sections were properly aligned if the splined portion was taken apart for any reason. If you are not sure, some of them have marks cast into the u-joint area in the form of a knot. I would have to dig through my literature to find the diagrams on how to align them.

Additionally, remove the driveshaft enough to flex the u-joint and see if there is a "notch" worn into the u-joint. If so, the u-joint SHOULD be replaced, but sometimes, you can change the position of the carrier ever so slightly and make the u-joint operate on a slightly different area, making the vibration go away. Do this by putting a washer between the carrier and the body at one bolt hole.

If all this fails, email Steve Brotherton (SteveBFL) at Continental Imports in Gainesville, FL. He has a source for a driveshaft shop that will rebuild it and make it smoothe as silk.

Good luck,

Larry,
Thanks for the tips.

This drivshaft only has a shde over 40,000 miles on it after a remanufacture..at dissassembly, for the conversion to 5-speed, the u-joint was checked as you describe and was OK. When it was reconfigured for the 5-speed, it was retubed and balanced by a shop in San Antonio that has a good reputation for quality work.

Flex joints are questionable but, are the same ones that were in the 4-speed and it vibrated then too.

The shaft halves have never been apart since the driveline was reworked for the 5-speed and, there is no discernable dynamic vibration associated with shaft rotation.

I'm almost positive that the shaft is OK.

The vibration I'm encountering almost has to be harmonic since it has no connection to the wheel speed (and thus the rotation of the shaft) but, instead is closely associated with engine speed, being highly pronounced at 1800 to 2100 RPM in 2nd, 3rd & 4th. But, I have no idea what frequency it is.

Another forum member sent me a survey of Euro drivelines that he's encountered and the common denominator on the 5cyl/manual tranmission combination is a vibration absorber. PN: 123 411 17 47

I'm working on acquiring one of these jewels.

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Never a dull moment at Berry Hill Farm.

Was that one a 240?

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Never a dull moment at Berry Hill Farm.

Yes, it was an 84 Euro, 240D.

Are you sure that your motor mounts and transmission mount are okay?

My engine mounts are only about two years old but, I'm not completely certain that they're all that great so I have a set of mounts, subframe bushings and flex disks to install before I go any further.

For the record:

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Never a dull moment at Berry Hill Farm.

After thinking more about this, I've got to look in my records to confirm but I think I replaced the front mounts after I installed the first manual tranny because of the buzz...but, there was little to no change in the vibration.

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Never a dull moment at Berry Hill Farm.

You have probably already discussed this, but did you change from an automatic to a manual, and if so, did you have the new flywheel balanced to the old one?

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Changed from auto to 4-spd manual, then to 5-speed manual. Did not balance flywheel...did not need to. You can rev engine in neutral, or with clutch disengaged, to 4500+RPM w/no noticeable or unusual vibrations.

Here are some threads of mine regarding the conversion, vibrations and other fun:

Original conversion thread

Vibration 1

Observations

Dashpot

5-speed on the property

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Never a dull moment at Berry Hill Farm.