drive shaft clonk

[AXS]

hey guys jus noticed a loud clonking sound in the front left hand side of my car whilst driving home after work, it seemed to be getting louder the faster i was going, after 60km/h the whole car was vibrating and shaking. so i went home and put the car on stands and had a look under to see what it may have been, everything else was working 100% just this weird sound was the problem, at the time i was thinking maybe the drive shafts or cv's gave way.

so im under the car and everything looks fine, so next thing i did was put the car in gear and switched it on whilst off the floor and i seen a part of the drive shaft (passenger side) spinning irregularly, and the sound was coming from there, what is that called? and do i need to change the whole shaft or jus that part of it. roughly how much does the part cost and roughly labour cost, just so i dont get ripped off at the mechanics...

thanks guys

http://i954.photobucket.com/albums/ae22/jdm818/driveshafts-1.jpg

[bennjamin]

thats a balancer and required it needs to be held firmly in place

[AXS]

thats a balancer and required it needs to be held firmly in place

does this mean the whole drivshaft must be replaced or can that get sent to a specialist to get fixed???