C70 2012 acceleration shudder / shake / vibration

[outdoorslife]

Hi all, first post, glad we found this site.
Local mechanic keeps changing parts but problem persists. Getting annoyed obviously, as I don't think they really know whats going on.

Symptoms are like others have mentioned in similar posts. Under acceleration, whether mild, moderate or hard, one can feel a shudder coming from the front end. Seat of the pants feels like cv joint, however steering wheel doesn't have typical shudder feel.
When sitting in the passenger seat, shudder feels more pronounced.

Work done to date:
10/2023
Tires replaced with new Firehawk A/S V2 (tires were worn)
2 engine mounts and torque arm
31262676-5, 31326498-0 and 9487349-4
3/2024
Right front CV axle assembly replaced
5/2024
Left CV axle assembly replaced

Basic diagnosic/try from reading posts:
When accelerating if I push it into neutral shuddering goes away, and engine rev's up. (of course I then let off the gas so as to not redline the engine)

Diagnostic notes (condensed)
10/23 - found engine mounts worn and should be replaced
3/24 - Looked overall components that were replaced, still look good. Believes worn right front cv axle and torn boot is the issue.
5/24 - Found left front axle boot torn, no play, but recommends replacing axle assembly.
Technician now notes that motor mounts and transmission mounts have excessive movement. [me: WTF, mounts are a yr old]


Not thrilled to go back again, since it feels and looks like shotgunning vs actual diagnosis.
The lower control arms haven't been replaced, but -supposedly- they are fine, IE no bushing damage.

If there are any thoughts on what we can visiually check or try to help narrow things down, that would be great.

If there are any thoughts on where we can take it to a volvo specialty shop, that would be awesome!
Know enough about cars, but no longer can repair, such is life.

We are in the greater Melbourne FL area.


Thanks!

[Lightspeed65]

Unfortunately I have no solution. It should be no consolation but I have exactly the same experience with the same car built in 2006. I have also been through almost everything:
New wheels, new tires, new drive shafts ... and so on.

I don't have new engine mounts yet, they are still the last option for me.

I read and write in four different forums. So far I've heard that in one it was the automatic transmission, in another the drive shaft and then again one of the engine mounts. And for many, like us, hardly anything helps.

What makes us different is a gearbox flush. It did nothing for me. Maybe for you? Flushing the geartronic and changing the oil.

I'm now following this thread just as closely. My C70 has been shaking for two years now. It's no fun and nobody has a solution. And my garage doesn't know what to do either

Hope, you'll get a solution soon.
Best wishes
Christian

[scot850]

A question for both of you. When driving the cars, especially yours outdoorslife, when you say you feel a little of the vibration in the steering wheel but you can feel a vibration from the seat.

I normally consider the 'vibration through the seat' issues to be from the rear of the car, not from the front.

I would be suggesting you look at sticking rear calipers and bad parking brakes/cables for the issues as well as rear suspension mounts and rear tracking.

Very frustrating for both of you.

Neil.

[Lightspeed65]

Hi Neil,

thank you very much for having a look at "our" problem. Suspension mounts is truly one of the next points to check. In outdoorlifes case it may come from the rear, in mine i'm convinced it's coming from the front. I can "feel" the vibrations through gas and brake pedal as well as the seat. Your hint to check brakes makes me rethink the problem into this direction.

It "feels" for me as if anything is loose or not properly assembled in the front and the shuddering comes from underneath my feet (padels)

Strange detail: There are moments, when the car behaves, as a T5 Volvo should behave, smooth acceleration, no shuddering. Especially in the first "cold" five minutes but also during a longer ride. In any case it appears under heavy load (hills up) and kickdown. It disappears downhill ... but the driveshafts have been changed already - no effect.

My next steps:
- checking engine mounts
- checking brakes
- checking suspension mounts /calipers

Your hints are warmly welcome, thanks a lot. Hope outdoorlife can too profit from this. I didn't want to steal his thread but his problems sounded so much familiar

I'll continue to report, maybe this will take it's time. But the car is a legacy from my father who bought it in the age of 81 and four months later decided to give up his driving license. From one minute to the other I became a Volvo-owner. Took a lot of money and nerves to work against an obvious maintenance backlog. But two years later there are only two topics on the list. Shudder and a dimming rear-view mirror which is not dimming. This beautiful car is worth the effort.

Never surrender.

Christian

[Krons]

I would definitely check the lower control arms with a pry bar to see if there is movement. The 08 C70 I had the control arm rubber was completely shot at 120k miles.

Also possible the shop used cheap CV joints and they aren’t up to the task. Verify what brand they used.

[Lightspeed65]

thx a lot. I will check your tips as soon as possible. Be sure: report follows asap too.

again thank you very much for your ideas.