My exaust (86db at idle) my diff, louder than that, my stereo, and my window down can NOT get rid of that sound. I doubt death its self could get rid of that sound. Even when we got rid of the thing I could still here it for a week after everytime I hit 105kmh.
But yeah, its the left knee thing. Make sure its the right one (the other will effect your alarm, door lights, left head lights on sound etc). When you have it, KILL THAT BARSTARD THING!!! THROW IT, JUMP ON IT, SHOOT IT!!! Yell BEEP BEEEEEP at it.
You WILL feel better.