I recently bought a 2002 Volvo S80 and we've noticed that when the car starts to pull or when we press the gas and we're going I'm going to say I guess starting at 45 and over it will start to shake and the fast you start to go the more it shakes. When you release the gas, it stops and is super smooth. We added power steering fluid since it was low and that seemed to help it a little bit at first, but it came back within 30 minutes of driving. My grandad thought it was one of the front wheel axles, but they are both not lose and he can't seem to find any thing lose under the car or hood. We took it back to the dealer and they had other people drive it and they said the tires were unbalanced so the re-balanced them, but the car is still shaking! Not as bad as it was, bus still enough to know its there and enough for it to be a problem. Again, it only shakes in the front end when the gas is being pressed and when it's pulling up a hill or doing 45-50 over. Can anyone PLEASE give their thoughts and suggestions. This is my first car and I really just want to know what's wrong with it.

 

Its either one or both of your halfshafts. This is a super common issue, and in fact, thats what Im fixing today myself.