Yesterday, my 2000 s40 developed a pronounced shake, and a clacking sound that speeds up with speed. At a slow speed it feels almost like a bent rim, but then around 60 mph its a quick shimmy. It sounds like its on the driver side. It started yesterday, then it disappeared for awhile at high speed (70+) and it didn't do it today until midway through my commute. I revved it in nuetral and the engine is running smooth, so its probably something in the driveline. It seemed almost like the wheel lugs were loose. I'll check that, but its probably not that. Any ideas???????????

 

I have the same problem now...did you ever figure out the cause?

 

could be a number of problems, one of the most popular among the s40's is the wheel being dented...check your wheels and your suspension, if that doesnt solve it than look into a warn motor mount...

 

Someone else had bad CV joints causing this. Not too hard to DIY but IIRC one side was hard to find.

 

well i drive a s60 and mine does the same. but it seems like the car has 2 warm up before it does it, some days WAY worse then others. i do have 2 bent rims so we switched them to the back, new aftermarkets on the way. switching the wheels 2 the back seemed to help it out for a little bit, but again as i say. when i cruise the slightest bit of acceleration causes my car to freak out and vibrate like crazy, it sorta scary, it feels as tho its gonna fall apart. im not sure either..

 

Check your axles as well.