Bad Vibrations...
 

OK, so I already know I need shocks & struts and I discovered recently that my upper engine mount is broken (bushing is seperated). I got a new engine mount today and plan to replaceit tonight. The shocks/struts are more money than I have unfortunately. I need to know if the horrible vibrationsare related to these issues or if there is an additional problem(s) that need to be addressed as well.

Somewhere between 45-70 mph (not always, just random) the car will start a violent vibration that feels more like an almost flat tire than anything else (no - my tires are fine). It will go away completely if I let off the gas but as soon as I press the gas pedal again it starts back up. After a while it will just go away. It rarely happens if I'm in the car by myself but if I have1 or morepassengers it's guaranteed to happen.

I'm scared to death I'm going to lose a wheel or something but this car is my only transportation right now. Please any and all suggestions are welcome.

RE: Bad Vibrations...
 

I had something like that happen to me, turns out I had a bent rim.

RE: Bad Vibrations...
 

99 Volvo S80 T6 100k miles

Same issue and took it to the dealer for a look.

New tires, balancing, 4 wheel alignment and still there. Dealer looker further and said the CV joints have some play in them. Just bought the replacment passenger side one from www.eeuroparts.com for about $100. You can find some good directions for DIY job inside the S80 posts.

I'm going to tackle later this week and I'll post an update

RE: Bad Vibrations...
 

Easy as pie. Just check the passenger side for that Visco clutch option. Mine had it and I did order the right one. The tell tale sign is another item behind the 2nd CV joint before the axle enters the transmission.

Dumbly put, it looks like there are 3 CV joints instead of two. If you have this, you have the Visco clutch.

Directions were excellent here http://www.matthewsvolvosite.com/for...ic.php?p=63174 just some bolt sizes being 1 size off. Otherwise an easy job that took 1 1/2 with 2 guys

Vibration all gone. Runs so good I may do the drivers side now!

To the OP. What did you end up finding ou about your car? I have the same vibration issues, occurance/speed/passengers/etc. I am thinking I need to replace the passenger side axle but wanted to see if that was your case before I order one up.

Sorry for not updating.

I replaced the upper engine mount and most of the vibration went away. Now it only vibrates under hard acceleration. I will be checking the CV joints next.