fstshrk

I had the motor and transmission mounts replaced on my 2008 S550 4Matic this week. Last two months, I felt a vibration between 1200-1700 RPM while accelerating and also while coming to a stop.

It was covered under CPO Warranty. The tech noted that all four mounts were completely collapsed.

I hope the new mounts are of a better design.

brianw430

Have the new mounts eliminated the vibration? I'm wondering how do you differentiate between bad motor mounts vs. bad tranny mounts? Can a tech determine with a visual inspection? Or do you simply replace both motor and tranny mounts at the same time?

Em Bee Lover

2007 4matic w/ 76000 miles. I replaced motor mounts and trans. mounts some time ago at my expense.

Still vibration in steering when when put into gear, coming to a stop and while idling at a stop light. Shift to neutral and it stops. I am still frustrated.

fstshrk

After you get them off the car and look at them side by side you can definitely tell.

brianw430

So em bee lover, have you continued your quest to eliminate the vibration? If so, what did you do next? Also, what was the cost of replacing both sets of mounts?

fstshrk, I was curious if you thought the cause of the vibration was from motor mounts, tranny mounts or a combination of both?

fstshrk

I can confirm that replacement of the motor and transmission mounts completely cured all vibration problems on my car.

I think the fix is to replace all of them. I think failure of one causes the failure of the other eventually.

brianw430

Thank you fstshrk! I'm getting a quote from the dealer of $1,080 to replace all three mounts...does that sound reasonable?

desired_speeds

I think that's on the high side.

Em Bee Lover

Brian--

I am tolerating the vibrations, unfortunately. The ones removed truly were crushed and very perceptibly "less in height" than those removed. Mine are identical to fstshrk's post....vibration in steering when putting in driver or reverse and while coming to a stop, as in a stop light setting. As I posted, if I put the trans. in neurtal, the vibration goes away. Verry frustrating.

I was out of warr. when work done. My trusted indi bought the fronts from an authorized MB dlr. and installed for about $400. The trans. was done later.

The only thing I can guess is the dlr. had mounts in stock that were the original version and not the MB released "fixed" ones. I have been trying to get the part number of those shipped from the dlr. Getting run around.

The net is if the engine mounts installed are the new and improved, not the originals, that was not the anwser to my vibration issues.

RA032924

Replaced my motor mounts at 41K, and idle vibration is gone. Replaced my tranny mount at 45K and vibration at 60-70mph is mostly gone (all under warranty). I am now at 70K and still vibration free. Sometimes I think I feel something at 60-70 mph, even on my newest tires, but my family thinks I'm crazy. I think $400-500 per job is about right, if I recall, but my indi saves me about 20-30% over dealer and he always uses OEM parts.

brianw430

Thank you! I am waiting for my indie to get a quote put together. I think I may just go ahead and have it done, preventively, as the vibrations are not bad at all now...but noticeable. I just can't help but think they are there for a reason other than keeping the driver from feeling the vibrations...like prematurely adding to the stress of both the motor and tranny.

Thanks again!

Em Bee Lover

I have been digging for more info.

Here's something that may be appropriate to all w/ vibrations.

P-B-22.10/01a AUG07 – 221.186 (4-Matic) up to VIN A127497; Humming/vibrations in the engine rpm range from 1200 to 1600 (clearly felt in the steering wheel and footwell floor), the dealer will install optimized engine mounts (part # A221 240 08 17).

My vin ends in 117123.

Thought I'd share.

brianw430

Great info...yep, thats me! My VIN, vibration, 1200-1600 rpm...exactly! Thank you for the appropriate part number, that's huge!

Is that part nunber for all three mounts? Or do you happen to know if there are three different mount part numbers? One for each mount?

Great info, thank you!

Bogdan.i.k

Have same problem here. Just replaced all mounts. and have vibration when in D and foot on breaks. Did you manage your problem?

Em Bee Lover

Did you manage your problem? Frankly, no. MB dlr. folks can't define/diagnose, local indi is tired of me whining. I left info/bulletins w/ him that addressed relieving the "tension" between engine and trans., loosening this, relaxing that. It has 90,000 on it. Hit dlr. lot 8 yrs. ago. Long answer is I put my mind on ignore at stop lights etc. Shouldn't have to w/ this level of vehicle. kinda disheartening, but mostly frustrating.

snovvman

Put me down as another with the exact same problem. Can it be transmission? Torque converter?

Nickthegreek

After replacing the motor/tranny mounts and doing a throttle body relearn my car now runs silky smooth at idle or in gear. Try a throttle valve relearn, it worked wonders for me. Has to be done using DAS/SD. After doing the mounts they eliminated 90% of the vibrations, and the relearn did the rest.

snovvman

Thanks. I'll mention it to my service advisor.

My car is 2013, Em Bee Lover's is 2007. In terms of drivetrain, the two cars are vastly different, especially the engine (therefore motor mounts). And although the transmissions are similar, I'm sure there are design changes also. It puzzles me that a few of us are experiencing very similar symptoms.

alx

New motor mounts should eliminate vibrations regardless if the are new or old version parts. Continued vibrations in gear at rest are usually indication of low rpms ie throttle body dirt, lack of relearned throttle body and/ or engine adaptations/ harmonization. It might be also carbon buildup.

snovvman

I am happy to report that new mounts *mostly* eliminated the vibrations. I would consider what I am feeling now to be acceptable. I am also being hypercricial because I expect a Bezn to be perfect :-) You know, "the best or nothing" thing.... The worst part about the vibration was the drone [vibrational noise] that came with it.

I live in California, so my dealer has not seen many 4Matic S550s. I know it took them a good part of the day to replace the mount and they realigned the car afterwards. This tells me that they had to touch some steering components to do the job.

Among all the causes already listed, the symptoms were also consistent with a marginal torque converter. The vibration felt like a chatter. Interestingly, I was given a TSB that described early W221s with bad TCs that had a vibration problem. I'm just glad it was not the transmission.