Shimmy in Rear End, mostly when accelerating

[badwulff001]

I have a 2002 S80 with 200kms. Late last year I started to develop a shimmy that was mostly felt in the rear end of the car at speeds of 80-110km. The shimmy is especially noticeable when accelerating and when the car settles down after going over a dip/rise in the highway. I live in MTL, Canada where the roads have dips and rises every 20 feet so it's pretty much constant! Bumps don't seem to make a difference either way.

It's not the shocks or the tires. I have done the following:
- replaced the rear shocks 2 months ago (no change)
- had tires rotated for winter rims, with alignment (no change)
- bought new 18"rims and tires last week for summer (no change)

Volvo dealer has looked at and test drove car twice. They can feel the vibration but don't know where it's coming from. They suggest to live with it because of the high mileage.

I can't drive it anymore. It's getting worse each week! Any ideas on what the techs should be checking?

[vegasjetskier]

Are you sure it's not the front end? Many times a bad CV joint will exhibit these symptoms. Also, out-of-balance wheels will do it, but with new wheels, your balance should be OK.

[badwulff001]

Are you sure it's not the front end? Many times a bad CV joint will exhibit these symptoms. Also, out-of-balance wheels will do it, but with new wheels, your balance should be OK.

I mentioned this to my mechanic, who says the CV joint looks fine.

The shimmy/vibration feeling seems to be worse when the back end of the car dips to one side or the other as the suspension absorbs rises and falls in the road service, and only at 60-70 mph. As I accelerate quickly over these uneven road surfaces, and pull the back end, is when you can really feel it.

Any other ideas? I'd like to give him a laundry list of things to look at.

[badwulff001]

I forgot to mention...

If there is weight in the back seat or trunk, the vibration feeling is worse...