W124 Highway vibration while accelerating - PeachParts Mercedes-Benz Forum

r_p_ryan · #1 02-25-2006, 09:51 PM

My 89 300TE recently started to hum/vibrate around 45 mph while accelerating or going up hills. It seems to get worse as speed/throttle increases and it happens in any gear. There is no/low vibration while coasting. The vibration has been slowly getting worse over the last few months. I occasionally use it to tow a utility trailer (approx 2000lbs) and it was particularly noticeable when taking the trailer to the dump today - haven't towed anything in about 12 months.

The car has about 230k miles on it, and I've put about 90k of them on it. I have never replaced the flex disks.

I read LarryBible's thread about doing some research before throwing parts at driveline vibration problems, also the part about altering the seat of the U-Joint looks like a good thing to try before dropping the exhaust and throwing flex disks and a center support bearing at it. But Duke mentioned that the flex disk should be replaced at 60k or else bad things happen so I'm wondering if I should just replace them regardless. While I'm in there should I replace the center support bearing? The car had an oil leak at the headgasket (which was repaired about a year ago) but this resulted in the undercarriage getting persistently coated in oil. Can that ruin a flex disk?

About the tires - they're about 12 months old and the MB dealer performed the last wheel alignment. Does this type of vibration seem like a tire problem? Should I rotate the wheels or swap them with my other 300E?

Thanks!

r_p_ryan · #2 03-01-2006, 02:12 PM

bump

A264172 · #3 03-01-2006, 02:28 PM

Do you have any shift related clunking down there? Best get under and give them a good looking over as 90k is a lot on flex disks. Once you get them changed youll hear/feel any other vibrations that remain. (If you do them... consider the lower shift bushing and tranny mount at the same time)

r_p_ryan · #4 03-01-2006, 09:43 PM

Thanks for the reply. Is the lower shift bushing the nylon bushing that connects the shifter to the tranny?

A264172 · #5 03-01-2006, 10:12 PM

I think this is the one:
http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1JV0QMRTI1QU1B4K0K&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1989&product=J4070-44817&application=000046642
...and I believe there is also a clip.
I had my front flex disk just short of come apart on me, in mid February in mid week, in a nice snowy cold spell. So I gave the job to my indie. (Ahh the power of a lift and a warm garage in the winter) He replaced both flex disks, the tranny mount, and the lower shift bushing with the parts I bought from Phill just as the old ones started to crumble, for $150.00 labor. I can't tell you how much better it feels. Smooth non-clunking firm power.

I can feel a little hiccup back in the differential now so I suppose those mounts are next on the agenda. Wish I had done the job myself so I could give you pointers, but alas, I can only testify as to the results.

anthonyb · #6 03-01-2006, 11:57 PM

How fast is the vibration? The driveshaft rotates at something like 3x the tire rpm, so if it's a medium speed "brrrrrr" it is probably more wheel related. If it is a high speed thrumming, it is probably the driveshaft. My driveshaft support bushing problem made a "thrumm... thrumm.. thrumm.." vibration, and it would also appear while accelerating through certain rpm ranges.

r_p_ryan · #7 03-03-2006, 11:01 PM

It's more of a thrumming - thanks for tip. I'll checkout the center support bearing. Is that the sort of thing that's easiest to replace along with flex joints?

anthonyb · #8 03-04-2006, 02:46 PM

Without having done the job (sent it to the dealer), I will venture that the answer is yes. At a minimum you have to shove the driveshaft back, don't remember if it needs to come out.