I suspect you need to check the universal joint in the driveshaft. Requires taking the shaft out and flexing it -- ANY roughness, vibration, binding, clicking, or looseness requires replacement (probably of the driveshaft) even if the defect is at high angle, much more than you would flex it in use.
Make sure the people who balanced the shaft checked it, and make sure that the clamp nut on the shaft is not too tight -- if you screw it down hard, the shaft will vibrate. It should be tight enough to dampen end to end vibration, no more, as the shaft does change length slightly as the rear suspension moves on the subframe mounts. You may want to look a the rear subframe mounts as well, and replace if not perfect, but since you report a drumming sensation on the shaft tunnel, it's either the rear tranny mount or the ujoint, or possibly a defective new bearing. It shows up at the resonant frequency of the rubber carrier. Peter Peter -----Original Message----- >From: Ralph Robertson <rare...@gmail.com> >Sent: Mar 29, 2011 7:35 AM >To: Mercedes Discussion List <mercedes@okiebenz.com> >Subject: Re: [MBZ] (SPAM?) Re: 1987 300SDL Driveshaft > >The shop that did the balancing was recommended by Rusty at MB Parts, so I >feel they are worthy of his recommendation. They did mark the correct way >to re-join the two sections, and the shop doing my vehicle work, was well >aware of the importance of getting the two sections put back together >properly. >I neglected to include the numerous wheel/tire balancing exercising that I >did first, as that was the most obvious. >The shop that has been working on this vehicle had the car up on a hoist, >and several times did the speed test after each mount/ flex disc. change. >The vibration is quite noticeable. They even had the rear wheels removed to >eliminate that aspect. The centre bearing and support was changed at the >same time as the support was very worn out letting the shaft droop. >The vibration feels exactly as though the shaft is not exactly straight, >with that flexing kind of vibration that would result. I can feel the >vibration in the shaft tunnel, as well as the floor of the car. I feel that >this may be culprit, but how to make sure the shaft is perfectly level, is >what I will pursue now. > >Ralph > >On Mon, Mar 28, 2011 at 9:54 PM, Jim Cathey <j...@windwireless.net> wrote: > >> Had the drive shaft removed, checked out and balanced at a specialty shop >>> in >>> Atlanta, Ga. It was out of balance slightly, and they added a weight to >>> correct this. >>> >> >> Just how familiar are they with 2-piece MB driveshafts? >> My money's still on that, especially if you are familiar >> with the different feel of the roughly 3x vibration frequency >> of drivelines versus anything else. Could the driveline have >> been mis-phased when it was reinstalled? About 27 wrong ways >> to line the two pieces up, one right way. See: >> >> http://userweb.windwireless.net/~jimc/JSLdline.html >> >> -- Jim >> >> >> >> _______________________________________ >> http://www.okiebenz.com >> For new and used parts go to www.okiebenz.com >> To search list archives http://www.okiebenz.com/archive/ >> >> To Unsubscribe or change delivery options go to: >> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com >> >_______________________________________ >http://www.okiebenz.com >For new and used parts go to www.okiebenz.com >To search list archives http://www.okiebenz.com/archive/ > >To Unsubscribe or change delivery options go to: >http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
