Vibration: Yet Another Question - Page 2 - PeachParts Mercedes-Benz Forum

Jareb · #16 10-25-2012, 09:24 AM

Quote:

Originally Posted by t walgamuth

Seems to obvious but did you check your lug nuts?

(Don't ask why I ask)

LOL...Yeah I checked them but good point. It usually pays to start with the simple things first.
This car has 312K miles but is a one owner garage kept and meticulously serviced vehicle. That being said, many of the parts are still original to the car. The flex discs and center support/bearing were the original factory pieces and although the flex discs were showing some signs of wear; they were no where near the failure point. Just goes to show how well these cars last with proper servicing throughout their life.
The only things not replaced at this point are the driveshaft centering bushings, the universal joint, rear differential support and any rear bushings.
I'm this far into it so I may just do it ALL!

Phillytwotank · #17 10-25-2012, 09:25 AM

$.02

Dif mount

rscurtis · #18 10-25-2012, 11:31 AM

I had a similar vibration in my signature car. I had three different driveshafts in the car, it was still the same. I suspected it was one of the axle joints, as the vibration was lessened with weight in the car, which would make the axle joints run just about straight.

I recently had the axles rebooted by CVJ, and installed them left to right to wear the other side of the joint. Vibration is gone, and is felt slightly on deceleration. These are the original axles, not replacements.

Keep in mind that a three-lobed axle joint combined with a 3.07 axle ratio will give just about the same vibration frequency as an out of balance driveshaft. If you really want to do some research, switch them side to side, and while they're out of the vehicle, run it in gear to check for vibrations, you'll only be running the DS and the ring and pinion. You can do it with the differential cover removed, the gears don't require any lube with no load, and you'll only be doing it for less than a minute.

Jareb · #19 10-25-2012, 11:53 AM

Quote:

Originally Posted by rscurtis

I had a similar vibration in my signature car. I had three different driveshafts in the car, it was still the same. I suspected it was one of the axle joints, as the vibration was lessened with weight in the car, which would make the axle joints run just about straight.

I recently had the axles rebooted by CVJ, and installed them left to right to wear the other side of the joint. Vibration is gone, and is felt slightly on deceleration. These are the original axles, not replacements.

Keep in mind that a three-lobed axle joint combined with a 3.07 axle ratio will give just about the same vibration frequency as an out of balance driveshaft. If you really want to do some research, switch them side to side, and while they're out of the vehicle, run it in gear to check for vibrations, you'll only be running the DS and the ring and pinion. You can do it with the differential cover removed, the gears don't require any lube with no load, and you'll only be doing it for less than a minute.

Thanks for the suggestion. The axles are new but that doesnt mean they cant be the culprit. I'll check into it further.
I'm also leaning toward the suggestion of "Phillytwotank" on changing out the differential mount too...it is 27 y.o. and 312K miles of use. I havent found a DIY on changing the diff mount...anyone have a link?
Thanks
John

vstech · #20 10-25-2012, 12:26 PM

support diff, remove 4 13mm bolts, remove center bolts (reverse order might make more sense...) assemble in reverse...

SD Blue · #21 10-25-2012, 12:33 PM

Sorry, I fail to see how anything aft of the transmission has an affect on a vibration that occurs when you are in Park or standing still.

barry12345 · #22 10-25-2012, 02:04 PM

[QUOTE=SD Blue;3035756]Sorry, I fail to see how anything aft of the transmission has an affect on a vibration that occurs when you are in Park or standing still.[/QUOTE

His first post states no vibration when in park. I have had some amount of indicated wear while the universal is running in about the same position all the time with two piece driveshafts. Always thought it was pretty normal and unless excessive put it back into service with no issues.

When you accelerate the loading of the engine side torque is increased. This to me could rotate the engine a little on the mounts and somehow introduce a felt vibration.

I might try cutting a length of 2X4 and put rubber on one end. Using it as a temporary engine brace and retest. You have pretty well covered enough already.

Try to remember that I approach some problems from a somewhat unorthodox way though. That piece of wood might help hold the engine and transmission in a more fixed position. I always like cheap tests and it is suprising to a simple guy like me how often they indicate something when I am unsure otherwise.

I dislike shotgunning type approaches when they are avoidable. The money spent can usually find a better purpose with little to no effort. I never let emotions apply to me when working on things either. They distort my limited judgement and abilities. So if I feel them flaring at all I leave the issue alone for awhile. Works well for me overall but may not apply to others. This is simply based on I tend to lose ground when I get mad or frustrated with anything.

Jareb · #23 10-25-2012, 02:15 PM

[QUOTE=barry12345;3035840]

Quote:

Originally Posted by SD Blue

Sorry, I fail to see how anything aft of the transmission has an affect on a vibration that occurs when you are in Park or standing still.[/QUOTE

His first post states no vibration when in park. I have had some amount of indicated wear while the universal is running in about the same position all the time with two piece driveshafts. Always thought it was pretty normal and unless excessive put it back into service with no issues.

When you accelerate the loading of the engine side torque is increased. This to me could rotate the engine a little on the mounts and somehow introduce a felt vibration.

I might try cutting a length of 2X4 and put rubber on one end. Using it as a temporary engine brace and retest. You have pretty well covered enough already.

Try to remember that I approach some problems from a somewhat unorthodox way though. That piece of wood might help hold the engine and transmission in a more fixed position. I always like cheap tests and it is suprising to a simple guy like me how often they indicate something when I am unsure otherwise.

I dislike shotgunning type approaches when they are avoidable. The money spent can usually find a better purpose with little to no effort. I never let emotions apply to me when working on things either. They distort my limited judgement and abilities. So if I feel them flaring at all I leave the issue alone for awhile. Works well for me overall but may not apply to others. This is simply based on I tend to lose ground when I get mad or frustrated with anything.

I understand what you suggesting here but my motor mounts are 2 days old and new MB parts. The only things not replaced are diff mount, driveshaft centering bushings and universal. I tried to replace the usual suspects first that cause a slight drivetrain vibration {driveshaft support and bearing, motor mounts, flex discs}> With the drivetrain having 312K miles on it; most every bushing/bearing/mount is probably at the end of life by now. No choice really at this point but to keep replacing the last few possible causes. All the obvious stuff has been done{at least I hope I havent overlooked something}

firstdiesel · #24 10-29-2012, 10:40 PM

I have the same symptoms in my car after doing the same work you did. Since my last post on this thread I did more highway driving and tried to recreate what you have done, and it is similar if not exact. I replaced flex discs, center bearing and support, diff support and motor mounts. Marked everything for assembly and took my time torquing everything. Only thing I did differently was that I did switch the axles after replacing the axle seals.

Please keep us posted of your progress. Thanks.

Jareb · #25 10-30-2012, 07:17 AM

Quote:

Originally Posted by firstdiesel

I have the same symptoms in my car after doing the same work you did. Since my last post on this thread I did more highway driving and tried to recreate what you have done, and it is similar if not exact. I replaced flex discs, center bearing and support, diff support and motor mounts. Marked everything for assembly and took my time torquing everything. Only thing I did differently was that I did switch the axles after replacing the axle seals.

Please keep us posted of your progress. Thanks.

I've been looking into this further. There are 2 companies that rebuild the driveshafts and they have been named in numerous posts. A company in Portland Oregon and Atlanta Driveshaft. You send them yours and its rebuilt with new universal, new center support and bushing, balancing etc for $350. BUT......they are no longer done in-house. Both companies stoped this practice 2 years ago and they are sent out to a "jobber". I inquired at both companies about the components used in the "Rebuild" and they use aftermarket stuff....NOT MB parts. This might be fine with some people but I've learned that if you want quality parts anymore...ya better do your homework! I asked if I could just get the universal replaced and I would do the center support and bearing etc....NOPE. You take the whole package or nothing. Just putting this out there so that anyone contemplating a new universal is aware that the only option is to DIY or take one of these. Also, of note, there is not one shop in Florida that I called that could balance a MB driveshaft and I called about 10 places! I'm sure there are a few somewhere but they are not easy to find here.
I will be doing this job in a few weeks so I'll repost how it turns out. New diff support, trailing arm bushings, new driveshaft centering bushings and subframe mounts.
At this point, I will have rebuilt just about every bushing, bearing, mount found in the drivetrain. Hopefully the vibration will be gone!
John

firstdiesel · #26 10-30-2012, 12:18 PM

Good info, John. Rear subframe mounts are next for me too. It would really be nice if it were the centering bushings though! I'm looking forward to hearing out it turns out.

Todd

firstdiesel · #27 12-10-2012, 10:19 PM

John, any update or fix?