Hi All,

I posted last month about vibration that appears to be coming from the rear-end of my 94 Volvo 960 Wagon (thank you for your replies). To make a long story short, my dealer replaced the driveshaft and since then the car has had a vibration/droan between 55-65mph. Upon taking the car back to the dealer they indicated it was probably the tires. After rim straightening and balancing the symptoms persisted so I ran the car on blocks with tires off and the noise seemed to come from the rear end. The vibration/droaning does not dissipate if I put the car in neutral at highway speeds and appears to be a bit more noticeable on deceleration. The dealer has the car and is so far stumped and says they rechecked the driveshaft for balance/phase and it is fine. I have replaced the Motor Mounts and the Transmission Mount. The driveshaft comes with new U-joints and Center bearing/donut so these suspects can be likely ruled out. The trans output seal has no leaks and visually looks fine. Same for the rear pinion seal. The new driveshaft is definitely in-phase as it can only fit together one way.

At the rear-end all bushings appear ok (no cracking, crumbling or smushing) but beyond the obvious I probably wouldn't know what to look for. The dealer believes the problem is either transmission related or rear-end related. I also replaced the differential fluid and when doing so discovered that it was "foamy" which fellow bricksters said was probably due to water getting in through the PVC vent.

Last, the car seems to have a very mild shudder under hard acceleration at take-off. Nothing signifigant but compared to my newer 97 960 wagon it does shudder at take-off.

I'd like some more ammo before I get a call from the dealer telling me that they can't figure the problem out. The car is going up for sale and it is something I want to resolve.

Any thoughts would be greatly appreciated.

Thanks!

Where did you get your rim straightened at?

Hi Ron,

Had a place in Newton, MA do the work. website is http://www.rimandwheelworks.com they do good work based on my one experience. It is roughly 100 bucks per rim (larger rims more) for a volvo 960 sized rim. You can also have the rims refinished/painted but i only opted for straightening. Not cheap but better than $250 plus for a new rim. They take rims that are shipped to them as well.

How about disconnecting the rear drive shaft and running rear wheels on a dyno or with one of those little motorized tire balancing things they use for on-car tire balancing? (Something like a dyno that would allow the weight to be on the wheels would probably be better.)

If the noise is still there, then you know it's somewhere in the differential/axles/CV joints/bearings, etc. If the noise disappeared, then it has to be somewhere forward of that.