V70 Drivetrain Thump?
 

Hi everyone.

I am looking for some help with my manual 232k mile 2004 V70 D5 please.

The problem is I have a thump in the drivetrain. When I'm driving and I let off the throttle for a few seconds, there is a noticeable thump/jerk as the drivetrain unloads. When I push the throttle again there is another thump/jerk as the drivetrain loads up again.

It's making it hard to drive the car smoothly. To be clear, it's something you physically feel, not a noise.

I have replaced the engine top mount and lower torque control arm but the problem persists.

I took it to my local garage (not Volvo specialists) who commented that the "engine moves around a bit" but couldn't identify the problem.

I have searched the forum without any joy on this particular issue. Anything else to look at at this point? Other engine mounts? Thank you in advance for any guidance.

Maybe the mount beneath the crank pulley (I assume diesels have the same as petrols).
Perhaps the front sub-frame mounts (engine cradle). There are 4, one at each corner. They go with time.

Thanks for the reply. I will be sure to check those things out.

To investigate further, I parked the car on the flat, in first gear with handbrake off. Rocking the car back and forth, there is a distinct clunk coming from the front right wheel.

Here is a video: https://youtu.be/_fsIrdB_dxM

Sounds like it's coming from the wheel hub. Any idea what this is and if it is connected to the driveline thump issue described above? Thank you.

Two real easy things to do:
1) Remove the center cap or the entire wheel and check if the center bolt (axle bolt) is loose.
2) The noise is "so big" that maybe a brake component is loose.

MAYBE (a real guess here) that ball joint is real worn.
MAYBE (another guess) the CV joint is damaged. One check for that is to go into a parking lot and steer tightly to lock and go in a circle. Do this in both directions. Select a lot with a wall so sound will bounce back at you.


Pep talk: If you raised the front end (both wheels off the ground), in Neutral and rocked the wheel as you did in the video I bet you could zero in on the noise's source.

Great, appreciate the response. I will dig into this further tomorrow and post the findings. I am kind of hoping the "thump" issue and the clicking noise are one and the same issue, not two separate problems!

Is it more noticeable after you've been driving for a XX distance/warms up some? I have a noticeable clunk too, not gotten round to fully diagnosing yet...

Some "bolts" were mentioned when i asked about this, forget which, cant find my post now lol...

Hi Bashy, no the problem is ever-present, regardless of miles driven or how warm the engine is.

I am taking the car to a mechanic later today so we can get it up on a lift and investigate further. I will post here what we find, hopefully it will help you diagnose your issue.

Update: the clunking sound was indeed a loose axle bolt - thanks Georgeandkira.

The drivetrain thump persists however, further investigation is needed.

yes 4 lower engine mounts plus subframe bushes, plenty to check

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