Eighteen months ago I bought my 2006 V70 with 38,000 miles from a new Volvo dealership. When test driven there seemed to be a slight vibration at speeds over 45 mph, and thought it to be a wheel balancing issue. I have been chasing this intermittent thrumming vibration in the front end ever since. The tires were replaced, wheels balanced many times, axles replaced and one new wheel and tire to rotate around the car,
test driving in between rotations. Four different shops, including two Volvo stores, inspected, test drove and could not diagnose this. The only thing they all had in common is the advice to start guessing where the problem might be and replace those parts.
Your help diagnosing this is greatly appreciated.