Center Support Vibration

[syzygy66]

Hi there, I drive a 1990 760 Turbo. I encountered a problem where when I would accelerate the car from a stop and/or climb a semi-steep hill, I started to feel a vibration which then became a banging under the car.

Fearing that it was the transmission, I took it to a local Volvo mechanic who diagnosed the problem as NOT the transmission, but that it was a worn out center support and bearing that holds the drive shaft in place. Apparently the bushing was shot and there was way too much play in it hence my drive shaft was banging up against the bottom of my car.

So he replaced the center support and bearing with (presumably) a brand new one. However, although the car does not bang like it used to, I still feel a definate vibration when climbing hills which is very annoying. I asked the mechanic about it and he advised that I will still feel some vibration despite the fact that the part was replaced.

Now my question is, does that make sense? In my naiveness, I would have thought replacing the center support and bearing with a brand new one would completely eradicate the problem. I haven't had a chance to investigate if the part is actually new, I'm taking his word for it at the moment.

Any help advice on this matter would most appreciated! Thanks.

Kris

p.s. he also replaced the transmission bushing and seal at the same time if that has any bearing of the situation. Thank again!

[syzygy66]

does anybody have a comment or suggestion on this???

Thanks,
Kris

[dpauto.com]

Kris,

I assume your 760T has multi-link rear suspension. What your mechanic did was a normal procedure (replace center support and bearing) when comes to driveshaft vibration. However, there are other places you need to have your mechanic to inspect.

1) check closely at the transmission mount, make sure it's not collapsed.
2) check all 3 bushings that hold up the rear multi link susupension....especially the upper one.

If any of the mount/bushings collapsed or broken, must be addressed first before >>>>> this final step.

>>>>>> Your mechanic needs to shim the the center support. This shimming process will either move your driveshaft center support up or down to eliminate the vibration. To raise the driveshaft center support up, washers will need to be installed between the support and the mount bracket. To lower down the driveshaft center support, washers need to be installed between the mount braket and body frame. To totally eliminate the vibration, the driveshaft center support will need to be either shimmed up or down. Your mechanic will have to play with the shimming until the vibration is completely gone. (example: if shimming up makes it worse, then you want to shim the opposite way)

Regards,
Dave