Hey folks.
So sorry for such a newbie question, but looking to solve a shuddering/vibration problem in my C70. Most indications pointing to engine mounts.
I found an article that said my C70 had only 3 engine mounts. A Volvo upper engine mount underneath the coolant reservoir, an upper transmission mount underneath the battery box, and Volvo torque mountwhich bolts to the back of the transmission. So I started to buy to the parts. I ran into two problems that are stumping me.
1) Seems as if the upper transmission mount is different if the chassis number is 487 or below than if it is 488 or above. Well I can't find the chassis number and if I assume it is the last 3 digits of my VIN then I am up over 740, which seems way over 488.
2) when looking I found a "engine torque damper mount" but also found an "engine torque arm" that looks completely different but that is made for my year of C70. I am trying to know if this is a fourth mount that I should replace or at least inspect.

Thanks in advance for any help or knowledge.

 

When does your shuddering/vibration occur?

Idling, accelerating, left turns, braking?

 

Accelerating.

 

Think I figured out the Chassis number question. Now I am looking for any sort of instructions or guidance for that Upper Transmission (Left side) Engine Mount.
All I know is that it's located below the battery tray and the part number is 31316498.

If anyone has replaced this part before and can help, I'd be much appreciative.

 

Sometimes/typically if you have a vibration when accelerating - and the steering wheel shakes - the outer constant velocity joint on the right axle (cv joint) is worn, or worn out. The solution is a replacement (quality) axle. There are many axles available of varying quality. Sometimes the axle you purchase is worse than the axle you are replacing! Even if it's brand new!

 

Thank you hoonk! The CV axils are definitely on my list, but I thought I'd do the engine mounts first. The car has 120K miles and I could see that the Right-side upper mount had been compromised so I replaced it already. Once I replace this upper (Left-side) transmission mount, and possibly the lower torque mount, then I will take it to the next level and probably do the control arms or the CV axles next. Seems that all of these parts tend to wear out on these Volvos at around 120-150K.

So...any experience or tips on replacing that specific Transmission mount (Left-side under battery tray)?

 

Yes - never saw a bad one, so my techs never replaced one! Only fixed what I could prove was bad for my customers. And shaking when accelerating @ 120k miles is classic worn right cv joints.

 

Hoonk - when you are right, you are right! I replaced the upper left transmission mount yesterday. Was easy enough - only cost me $70 in parts and about 90 minutes. Only had to lift the battery out, take out the battery tray, and then there were 4 nuts and a bolt to remove. The mount did look like it had a lot of microcracks and a small leak in it, so probably not a bad thing I replaced it. But as you predicted, it did NOT fix my problem. Looking to buy new front (left and right) CV axle assemblies now. Do you have a brand recommendation? Also in your opinion, should I look to buy boot kits only or the whole axle assembly?

 

Buy GKN ones, not the cheapest ones you can find. You need the whole shaft, not just the boots. I replaced mine in the parking lot, it's not a bad job. Mind you, replacing the shafts did not cure my vibration issue, the motor mount you replaced (under battery) helped more with that. I am down to replacing the auto trans fluid as the last possible culprit but since the vibration is now pretty mild, been putting that off. But on another Volvo (S80) that had a vibration problem the driveshaft WAS the issue so could be yours as well.

 

To close out this thread, it was ultimately the CV axles that were causing my vibrations. Replacing both sides and getting an alignment made teh issue go away. I also replaced the two other motor mounts (had previously done the upper engine mount that did not fix the issue). Looking back, I may or may not have really needed to replace all three mounts but I did it anyway.

For info - the mount that gave me the most problems was the "upper transmission mount" which is the one located under the battery. What I did wrong was 1) did the job in my driveway which has a slight incline, and 2) used blocks and a hydraulic jack to support the engine while I tried changing the mount. Dumb move. What happened was... (you savvy mechanics already know what I am about to say any you are already laughing at my stupidity) ...the engine dropped ever so slightly and the holes for the mount misaligned the minute I removed the old mount! I struggled for over an hour to reposition the motor with prybars, and almost had to have it towed, but got a real mechanic buddy to come over and help me and we eventually and miraculously got the mount bolt to grab and got the job complete. I hope someone reading this learns from my error.