Hi, folks:

Didn't get a wheel or rotor off, but did take a "ride" last night with a friend who is a mechanic for an area fire department - 19 years experience. We got it to duplicate the sound only once, but he instantly concurred that whatever is setting up this vibration is not a function of road speed or engine speed. He feels that pretty much rules out suspension, or even drivetrain, since that will be causally related to the road speed.

His reason ? It's that the vibration has no apparent relation to the speed of the car or the speed of the engine. It's so clearly defined that it's almost as if a switch were thrown, turning on the vibration -- suggesting an electrical circuit is being closed when it shouldn't be. He's tending to think ABS, since there's not really anything else back there that could "set up" a big vibration. Also, the lack of change in pitch or intensity of the vibration -- it's either doing it or it's not.

Could something in the ABS be activating only one side ??? Or activating in an abnormal manner, setting up a vibration nothing like the vibration felt through the pedal during normal ABS operation ????

We have yet to pull a wheel or rotor, but we will certainly run that down.

In the meantime, maybe the one other guy in Volvoland who has ever experienced this will read this, and save me hours in the heat popping a wheel and rotor........

Thx !!!!