I have recently begun having this exact same problem with my 2004 Volvo s40 t5 and haven'gt been able to diagnose it. Did you ever figure out the cause and if so what was the repair recommendation and estimate? Please and Thank You
2004 Volvo recently started to sound like something was loose when driving. Then the vibrating started. My mechanic took off the right passenger motor mount . Yes, it was damaged . I'm planning to fix it soon. FYI . The 2004 Volvo for some reason made a 2 different motor mounts . There is a $100.00 kind and a $200. With my luck .. I had to purchase the $200 dollar part ..