pulsing noise and tire kicking

hey all,

so there's this awesome pulsing noise when i make sweeping turns at 40+ mph, and it occasionally happens when braking coming off the highway as well. not to mention that there's a lot of noise from the rear of the car when going over a bumpy road at low speeds.

so i get out of the car today, and for some reason was drawn to kick the driver's side rear tire. when i kicked the side of it towards the back of the car, the tire shimmied a little and there was this wonderful metal banging noise. none of the other tires exhibited this behavior.

what do you guys think? tie rod? something else? please tell me it's expensive

thanks for the continued help,
dan