You are describing the limp home setting of transmission. It takes off in 3rd gear so it is gutless but once you get to the speed range where it would be in 3rd gear normally it feels normal. I am fairly sure that is not a part from a volvo. It looks like a broken piece of a rubber damped serpentin...

Unfortunately no part number

A friend of mine borrowed my S60, returned it to me with transmission problem. Car won't go into gear, only when reved high, it barely moves, but if pushed it will get going and once momentum is built it drives fine, until I get to a stop sign, then have to start over again. Also, found this part in...