Transmission mount alignment - PeachParts Mercedes-Benz Forum

latief · #1 06-07-2010, 07:42 PM

Guys,

Finished another project today, I changed my engine and transmission mounts...what a fun job that was

Here is my question. I removed the transmission support bracket to access and remove the transmission mount after changing the main engine mounts....

I noticed on the bracket that the over sized holes were not centered correctly originally (on purpose i guess)...i tried to center the bolts and bracket, but then the transmission mount would not sit correctly...so i changed the mount and bolted everything back together as it was before the job....

is there a special procedure to align the drive train correctly? or is that the way it should be?

thanks

mbdoc · #2 06-09-2010, 09:00 AM

AT dealer we do that on a drive on rack, so that the full load is on the suspension & tires.

Then push up on the drive shaft & trans (lift) to remove any tension in the driveline, and then tighten the bolts.

latief · #3 06-09-2010, 09:13 AM

Thanks,

Can you explain where you lift the drive-line from? and which bolts are tightened cross-member or trans. mount? I am getting some rumbling/vibe. at idle when in gear...

thanks

latief · #4 06-09-2010, 02:03 PM

So i tried this.

Supported the transmission and drive train with a jack while car on flat ground. loosened bolts holding the transmission mount to the cross member, and the cross member bolts. then tightened the transmission mount bolts first, then cross member bolts.

it idles better, but still with some vibration with AC on and while in gear only..
less than before though..

did i miss something? what bolts to loosen/ tighten first?

thanks,

Spetz · #5 06-10-2010, 07:21 AM

I would think that you loosen the mount bolts first, then the x-member.
After that you'd need to drop it and take the top mount bolt off.
Replace mount, tighten top mount bolt, then lift it and tighten the x-member bolts, and finally the 2 lower mount bolts.

However, the way you tighten it etc shouldn't effect your idle.
And, are you sure it's your transmission mount and not your engine mounts?

Also, did you find out if the transmission mount bolts should have threadlock?

big dog 2 · #6 06-10-2010, 09:16 AM

Yea, I have the same vibrations too when the air is on and in gear. Think I will just live with it for now.

Spetz · #7 06-11-2010, 02:44 AM

http://www.ps2cho.net/downloads/MB%20CD/W124/w124CD1/Program/Engine/103/22-2130.pdf

I found this which seems to address at least part of your problem

Spetz · #8 06-11-2010, 02:48 AM

By the way, it mentions that the engine stop must be set at 1,000 and 10,000km
What is the engine stop? And what is involved in setting it?
Or is this just to tighten everything again?

latief · #9 06-11-2010, 08:52 AM

thanks Spetz, my car does not have a stop, neither does yours i think....

I think the problem might be the front mounts......I will reset them today and see....

J. M. van Swaay · #10 06-11-2010, 10:14 AM

I also have wondered about the alignment of this mount. Thanks for asking the question.

Don't know if it's correct procedure or not, but what I do is reinstall in the same position as it was before disassembly. By looking carefully at the washer marks on the bracket, you can get it very very close...........

I suppose if the new mount is dimensionally different than the old mount was when it was new it may not work, but it's the best solution I could think of.

J. M. van Swaay

Spetz · #11 06-11-2010, 01:38 PM

Well according to the manuals the engine/tranny should be "shaken" a bit for it to settle before tightening.
I guess as someone mentioned, maybe the engine should be turned on for a few seconds and switched off