I think my posi is shot

[72chevyLWB]

I just picked up a vibration tonight. I jacked up the rear and the rear end felt funny when I turned the wheels. I took off the cover and the interior parts of the posi seem to be loose. There is a funny looking clip (not c-clip) the wiggles around and the springs will sway back and forth. I didn't notice this before. I also have a loud clang when the truck downshifts. It would only do it before when the tranny downshifted itself before, now it does even when I downshift. How much does it cost for a kit to redo a posi? I will put in the open rear tomorrow.