crowtree99

2006 CL55AMG with 67k miles on clock
I have owned for over a year now and has had same "issue" since purchase, has not gotten any better or worse and is more an annoyance than a problem so far.
I get an odd vibration I can feel through the car starting about 51mph which then smooths out about 62mph and then at 67mph upwards I would say is normal Mercedes fair, silky smooth.
I do not believe it is tires as have all balanced twice by different companies and rears were replaced about 3k miles ago and no change whatsoever.
What is also a little odd is it is worse when cold, as car warms up it is still there but nowhere near as bad.
Initial thoughts are maybe tranny mounts as it almost feels like it is underneath me, not so much as coming through the steering etc.
Any thoughts or suggestions?

biker349

possibly tranny mounts, or and engine mounts, tires, rims.

crowtree99

Possible very expensive maybes there...lol
But here is some more info that may help
I think the actual roadspeed is irrelevant so likely not tires/rims
I was driving at a steady 52mph today with the vibration present this equals approx 1500rpm on the tach.
I manually downchanged to 4th, same roadspeed of 52mph but now approx 1950rpm and vibration totally gone
Downshifted to 3rd same roadspeed, now approx 2450rpm and still no vibration
So it appears we have something going on starting around 1400rpm up to approx 1800rpm, at least in 5th gear.
TBH when I also dropped roadspeed to get 4th down to 1500rpm the vibration never seemed to reappear
Interesting......

crowtree99

Totally overwhelmed here.......

fireman685

You're about to enter into a mileage range that will be expensive. If the engine and transmission mounts have never been replaced then start there because they will be bad and the tranny mount is notorious for driveline vibration. Have the flexible couplings, or disks some say, on the driveshaft checked. If they are cracked they will cause vibration. Don't rule out your front tires either if they are not fairly new. Replacing them on mine solved some vibrations issues for me. Have your front lower control arms inspected as well. The bushings will almost be on there way out also in the 70-80k mile range.

crowtree99

Is there any way to tell by visual inspection that the motor mounts are bad? Also I have read it would be a waste of time to replace just the tranny mount as if the motor mounts are bad they will destroy a new tranny mount in short order.
It looks like I need wheel it in to my local MB specialist and have them check motor and tranny shafts and flex discs all at same time.
I still doubt it may be wheel or tire related simply because it ONLY occurs in a very narrow rpm range, not speed related at all.

fireman685

You'll need to get under it to be able to visualize the mounts but if they are bad they'll probably be leaking and yes go ahead and replace the tranny mount since its so cheap and easy.