I've been working (on my new to me 2008 C70) on what appears to be a not uncommon drivetrain vibration issue. One previous owner, and I have complete maintenance history.

Intermittent at low speed or under acceleration vibration. Doesn't feel in the steering wheel but in the floor etc. Tires are new, purchased prior to me buying the vehicle. Sometimes, most times smooth as silk especially while cruising. Other times at slow speed access or access to pass it shakes.

So far both right and left axle have been replaced. Left and right engine mounts have been replaced. Two piece transmission torque mount was replaced. Tires balanced yesterday. IPD tower brace installed. Planning to change out the spark plugs next week.

My question is, is there another transmission mount or other mount on the car. Been searching the threads but just haven't found a definitive answer for the later 2007 and up C70's.

Any help on that question? Any other ideas or advise?

Thanks in advance for your kind assistance.

 

Were the axles replaced recently and after the mounts were done? I have a similar issue with my 2000 C70 and its the drivers side cv that is bad. I know when the mounts go they can make the CV joints wear quick and shuddering on acceleration can be a symptom of a bad CV joint. Mine vibrates under anything but very light acceleration but is smooth at cruise. Sorry I can't help with the mount question.

 

DS, thanks for the note. Both axles replaced. Going to change the spark plugs tomorrow. We'll see what that brings.

 

Mine does this also. I tried everything: both axles new, motor and trasmission mounts, tires. Replacing the driver side engine mount made the biggest improvement, but the vibration is still there, just a bit when accellerating at lower speeds. Annoying and not supposed to be.
My guess is the cause is inside the auto trans on the driver's side. Because even the new OEM driveshaft has just a bit of play where it connects inside the trans. I even added an additional thin 50 mm bearing there to help secure the driveshaft, but the play is inside the trans, so nothing can be done short of replacing the trans. We'll live with it, my wife and son don't even notice it (but I do!).
If you have a more serious vibration under liad, chances are it's a CV axle. Buy good ones, not $100 ones.

 

After much work, including mounts, axles, flash the trans, struts etc. I finally seem to have resolved the transmission vibration issue. I had my mechanic completely replace the transmission fluid. Though it's not called for unless the vehicle has been used for towing, which mine had not been, based on my research I had found this to be recommended. With 104K miles on the car I thought why not. Problem solved.

 

Thanks mortrubl, that's a great tip that I will be sure to follow up!