Trans Mount Replaced (E420 W124) Vibration? - PeachParts Mercedes-Benz Forum

dproudfo · #1 10-05-2008, 02:29 PM

Slowly but surely I'm bringing my E420 back to life. (Picture of the car is below finally) I know there have been posts on replacing the trans mount on the 320s but not on the 420 (different looking mount) for the 124 so I thought I'd post my experience. Attached is a picture of the shot mount with the rubber completely disintegrated. The replacement takes maybe 10 minutes with proper tools. (jack up the transmission, remove center link, replace mount)

Now to the question I have. I still get a vibration through the car when the compressor is running. It's a low drone that's rhythmic in its frequency. I can't think of what else it could be. (tensioner maybe?) As of now I've replaced both engine mounts as well as the trans mount. Any input on the issue would be great.

Thanks!

dproudfo · #2 10-09-2008, 04:12 PM

Revised Symptoms:

Car has a vibration that cyclically runs through it when in D at a stop. If while holding the brake you rev the rpms up just a tad, the vibration goes away. Same when I shift the car into Park. The only post that was closely related to the symptoms I'm having was this:

'95 E420 - Vibrations in Steering Wheel at Idle

But his vibration goes through the steering wheel more it sounds like. (and he never solved the problem

.)

-Keep me posted.

dproudfo · #3 02-09-2009, 12:49 PM

Refresher: Symptoms, oscillating vibration through cabin when the car is in Drive or Reverse only. (vibration in steering wheel as well) When car is in Neutral or the RPMs are revved up in gear, vibration goes away.

The vibration has progressed over the last month so I've decided to tackle the problem. I used a stethoscope to listen to all elements of the serpentine belt (water pump, alternator, etc.) while the car was in Drive to listen for any irregularities (specifically the Tensioner). The Tensioner was the only thing that sounded off. Between Neutral and Drive there was a noticeable difference in the vibration of the pulley (random but subtle clanging sound) and the noise of the bearings. So I pulled the belt and the bearing in the tensioner clearly made noise and wobbled a little when I freely rotated it so I've decided to start with a replacement of the belt and pulley and go from there. My fingers are crossed that this resolves the problem.

I'll keep the board posted!

dpetryk · #4 02-09-2009, 12:53 PM

Sounds like bad motor mounts. Your rear mount looks OK to me. Are you sure the "disintegrated rubber" is really that way? The reason for the question is that those mounts have some thin sections that are not really needed for the mount. It is where the two mold halves meet. The rubber that is important is the thick stuff. From what I could see yours looks OK. But the picture is a bit dark in those areas so I could be wrong. Since you changed it and no difference in the symptoms says that the mount was OK.

dproudfo · #5 02-10-2009, 12:04 AM

Quote:

Originally Posted by dpetryk

Sounds like bad motor mounts....Since you changed it and no difference in the symptoms says that the mount was OK.

Motor mounts were replaced in August and the transmission mount was done in September of last year.

dpetryk · #6 02-10-2009, 06:49 AM

Well I guess that is not the problem.

280EZRider · #7 02-10-2009, 09:24 PM

Quote:

Originally Posted by dpetryk

Sounds like bad motor mounts. Your rear mount looks OK to me. Are you sure the "disintegrated rubber" is really that way? The reason for the question is that those mounts have some thin sections that are not really needed for the mount. It is where the two mold halves meet. The rubber that is important is the thick stuff. From what I could see yours looks OK. But the picture is a bit dark in those areas so I could be wrong. Since you changed it and no difference in the symptoms says that the mount was OK.

I agree. Check the drive-shaft centre bearing & its mount; you should be able to move it about 1/4 inch side to side. Also check the disks for shredding.

tinypanzer · #8 02-11-2009, 09:14 PM

I dunno about the drive shaft bearing, he says he's getting the vibration even at a stoplight.

Has the trans been serviced recently? Wrong fluid can freak out the torque converter and make it vibrate. Just a WAG.

-tp