Nickthegreek

Hey everyone. I've been having some vibrations in the drivetrain, mainly when I come to a stop. I changed my engine mounts in June so it's probably not them so I'm suspecting maybe the tranny mount. Anyway I'm going to see if the dealer has a mount in stock and I'm going to replace it today. I will post pics of the project. It looks pretty easy and straight forward. I've done the one on my 03 e320 w211 it was real simple.

Nickthegreek

UPDATE: Looks like Wednesday I'll be getting the part

castroadan

I have 08 s550 4 matic and I also am experiencing vibration at idle but only when in drive and I have my foot on the brake.

Is it the same problem you are having?

The vibration goes away when I let off the brake.

Garticus

Check for tranny leaks.

If/when the tranny is leaking....the fluid deteriorates the engine and tranny mounts thus this might be causing the vibration you feel.

With the engine running but held firmly in its mounts and the tranny not being held firmly in its mounts is why you may feel the vibration when stopped. (So a MB tech told me)

Nickthegreek

Mine is more when im in motion and about to come to a stop. I feel a vibration in the wheel and the car when theres a final downshift and the engine brakes.

Nickthegreek

Could be the engine mounts

Nickthegreek

Im suspecting tranny because i just changed the engine mounts and dont really have much vibration at idle now. But when the engine downshifts coming to a stop theres a momentary vibration that is very noticeable but goes away once the momentum/load on the engine is gone. Probably because of the explanation you gave Garticus. It would make sense that the tranny mount is mayne allowing too much motion.

Nickthegreek

If that does not help i am going to suspect maybe throttle body

Nickthegreek

Does it happen when in neutral or park also?

castroadan

It does not happen in neutral or park. Only in drive with my foot on the brake.

Nickthegreek

Im suspecting engine mounts then. Made a huge difference when i did mine

Nickthegreek

Looks like delivery got pushed back to Fri :/ Dam crappy weather!!!!

mbzphil

Mine also is when in motion and about to come to a stop. I mostly hear vs feel a vibration. Definitely cold weather only <32. The colder it is the more I feel the vibration though. The dealer at the last oil change said the engine mounts were just ok. They did not check the tranny mounts. Is yours a 4matic? Also is it required to be completely hoisted to change the engine/transmission mounts? I am interested in the amount of time if you would be willing to keep track. Thx.

Nickthegreek

Yes mine is 4matic. The engine mounts require a hoist to lift it up about an inch and a half. Took me an hour and a half to do the engine mounts. Theres one bolt thats a pain in the *** that holds the heat shield on and it is facing the back of the car. You have to snake your hand down the side of the engine along where the exhaust manifold is and loosen that bolt, then another one that is easier to remove. and then the heat shield comes off and exposes the bolt that connects the mount to the engine bracket. The bolts from the mount to the subframe are not bad to get out. At the dealership, it says you have to remove the exhaust to get the mounts out of the back but i found out a way to get them out of the top. You have to move the hoist over and then pry on the engine a bit and it will squeeze out.

For the transmission mount you just have to support the transmission not lift it.

Nickthegreek

Oh and you also need a stubby wrench to get the bolt off that connects the bracket to the mount. Sears sells a wrench for that. I can post a pic. Getting those two bolts out was what made the whole job a pain in the ***.

Nickthegreek

Also on 4matic dont lift the engine too much because the drive axles will hit the subframe and take a lot of stress. Theres a hole in the subframe that the drive axles go through.

Nickthegreek

Ok got the old tranny mount off and putting the new one on. Then going to take it for a test drive and let you guys know how it works then do the write up. At this point I am highly suspecting it was the tranny mount because the old one had way more play and would click if I twisted it. Ill have to say that for such a large engine and tranny it is not a very robust mount.

Nickthegreek

The vibration is barely noticeable! It also eliminated vibrations while accelerating because it was smooth as butter on the expressway. I figured it was wheel balance. Write up to come. MBZPHIL, it took me alot longer than I thought to do it because of the weather here. 2 and a half hours but only because I had to go inside every 15 minutes from frostbite and dripping water all over me. Had it been nice out I figured half hour to 45 minutes tops. Write up to come

Nickthegreek

Ok time for the write up. Tools needed:

-13mm socket
-16mm sockey
-E12 TORX socket
-various wratchets/extensions
-8mm socket
-floor jack (2 are preferable but 1 is fine)
-jackstands
-piece of 2x12 or suitable wood
-torque wrench

-power/air tools are optional but reccomended especially for the little belly pan bolts and the crossmember bolts to make the job faster

Nickthegreek

Jack the car up and put on jackstands... shoud be self explanatory. No need to take the wheels off. I had to modify the jackstands to mate into the lift points. Not hard just have to hacksaw off the ears.


Next remove the belly pan using 8mm socket and i used an electric driver. Theres alot of bolts so id suggest using an electric driver or it will take all day. There are i think 14 bolts holding it. I omitted a few last time I did my tranny fluid so that it will come off easier.

Nickthegreek

Ok now you have the tranny exposed. Theres going to be a large crossmember with 8 16mm bolts. DO NOT remove them until you support the transmission. There are also 5 13mm nuts that you can see bolted to the crossmember. You can remove these 13mm nuts for now.

Nickthegreek

Next put a 2x12 piece of wood block on a floor jack and jack it up until you just start to see the tranission lift then stop. Then remove the 8 16mm bolts from the cross member. I used a 1/2in air gun to make it easier. They were on there good. After you get the last bolt off the crossmember, it will come crashing down and is kinda heavy so support it if you can.




Now the transmission mount will be exposed. There are 4 torx bolts holding it to the transmission. Sorry my picture got screwed so ill show where the four bolts are on a pic.of the mount itself. Youll see them and be able to access them easily. So next remove the four bolts and it should come right off.

Nickthegreek

The four bolts are E12 torx.

Ok now its time to put everything back in. Put the new transmission mount in and start the threads. Its hard to screw up putting in the mount there are guide dowels and it fits the contour of the transmission pan. torque them to 28nm or about 20ftlbs.

Next set the crossmember up so that the holes line up at the body of the car and the bolts on the mount fit through. I used two bolts to start it diagonally in opposite corners. Then start each of the rest of the bolts. Torque these bolts to 45nm or about 33ftlbs. I gave them just a tad more for good measure.

Now you can lower the floorjack. Next put the 13mm nuts onto the bolts and torque them to 20ftlbs as well.

Now install the belly pan and enjoy your ride

The part was $102 at the dealer. Not too bad

Nickthegreek

Disclaimer: Due to factors beyond my control, I cannot guarantee against unauthorized modifications of this information, or improper use of this information. I assume no liability for property damage or injury incurred as a result of any of the information contained here. I recommend safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment. No information contained shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this is the sole responsibility of the user.

marthyh

Great write-up thanks!!