2000 V70 XC vibration at 15-20mph

[goVolvo]

Hi there,

Just make the title clearer, my V70XC vibrates at 15-20mph, around 1500-2000RPM. Typically it is when I am cruising at parking lot, not even pressing gas pedal. Once go higher or lower speed, then no more vibration. If RPM is higher than 2000 when accelerating to this speed range, slight vibration is noticeable but not so obvious. When braking down to this speed range, slight vibration also noticeable.

Lower engine mounts were replaced and mitigated a lot for this kind of vibration. In other speed range it is quite good, no obvious vibration though still not silky smooth.

Steering wheel shows this vibration very clearly. I can see the steering wheel blurring with the vibration.

Is this problem with CV joint? steering parts? Transmission or maybe one unbalanced cylinder?

Any insight is welcome. Thanks.

[scot850]

Used to have a similar problem with a 93 850 auto we had. After thinking my trans was failing, it turned out to be an out of balance aftermarket drive-axle. Replaced with a good OE shaft and car ran super smooth after that. Seemed to happen around 2000rpm.

Neil.

[goVolvo]

Used to have a similar problem with a 93 850 auto we had. After thinking my trans was failing, it turned out to be an out of balance aftermarket drive-axle. Replaced with a good OE shaft and car ran super smooth after that. Seemed to happen around 2000rpm.

Neil.

Hi, very nice to hear similar experience and solution. Which side is the drive axle? How to check if it is balanced or not? I'll do some research... Thanks.

On my car, one of the corrugated rubber boot on front right driving axle looks stretched. The middle ring ridge on the boot collapsed. Could be caused by wrong length of the driving axle?

[jblackburn]

Try some tight U-turns or turns at or near full lock in a parking lot. See what, if anything, makes weird noises. Sounds like a CV joint might be binding up on you.

[scot850]

It was the left one in our case, but could be either. jblackburn knows way more about these than me, so his advice is good. In my case it was just a crap EMPI axle-shaft. Ended up changing both out after less than 20k miles as both boots started to fail due to cheap rubber.

My limited experience is that the axles tend to bind more when off the ground. So after you have tried the sharp turns as advised, jack the front of the car up, put it on axle stands under the front chassis legs by the control arms, put the trans in neutral using shift over-ride, and turn the wheel while lying underneath and feel for snatching from the cv joints. With luck, this may guide you to which one it is assuming this is the cause.

Neil.

[E Showell]

Yep. I had an Empire EMPI (Chinese) axle go bad after about 13,000 miles. They are inexpensive (and cheap) and will work as a stop gap repair if that's all the budget permits at the time, but know you are condemning yourself to doing the job over in a year +/_ depending on how much you drive if you use an EMPI axle.

[goVolvo]

Went to a trusted shop today and they replaced the two front driving axles (cheap EPQ brand). Feel much better now. It was feeling like the engine shakes and is going to die, scale 8 of 10. Now maybe only 2 of 10. Not silk smooth but almost not noticeable if you don't try to catch it. The AWD driving shaft and rear driving axles probably play a role in it too. The shop suggests to get it done at another local shop that happened to have an used one available. But I feel it is good enough now. If getting worse later I'll try DIY it.

[goVolvo]

I want to report back, after two days and about 50 miles the problem comes back. So the front driving axles are not the source of the shakes though it helped mitigate the problem.

The old axles were able to be wiggled a little while on the lift. It probably worn out to some degree. With the new axles the front does feel much tighter than before.

For the shake I did some experiment and observed:

- It is most obvious at 16mph.
- Not related to engine RPM. I tried shift to neutral and rev the engine when the shake happened around 16mph on a safe clear road. The shake remains the same, same rythm, same intense. This probably is enough to see engine is isolated from the problem, and transmission is also not related.
- Exhaust pipes probably is shaked by the vibration and creating noise too.
- At 30mph, ther is no shake but higher frequency vibration, and humming noise, probably from the vibration of car body, but not sure.

So as long as the car is moving at such speed the shake always happens.
I have some wild guesses:

- Alignment. As the steering wheel is affected, alignment part probably needs to be checked, though it runs in straight line pretty well. This may explains that after new front axle is put on, the problem is mitigated. After two days, something is slacken off and the problem happens again.
- Wheel bearing. I did't have experience on this but it sounds suspicious.
- AWD driving shaft and rear driving axles. Not sure how big this factor is. But at neutral there is no much torque on the shaft and axles. They should not create so much shake even worn out somehow.

Any insight?

[jblackburn]

I think I would drop out the driveshaft to the rear wheels and take it for a drive.

Wheel balance that drastically off would be a huge issue at higher speeds. Wheel bearing should also make lots of noise at higher speeds as well (a loud drone or whap-whap noise at 40+).

[goVolvo]

S.O.S. !
What tool is better for those Allen cap screws? I used an Allen hex key and made two of them half slip, on the front joint of propell shaft. Rear and middle part is all taken off OK.

Sorry scewing things up. Worst case I'll have to put it on and bring to a shop.

It is right above the exhaust down pipe. Probably scortched for too long.