9"clicking

I don't know much about the rear, just bought the car. Rocking the car back and forth, I hear a clicking . Is this normal, could be a posi or locker? I don't want to ruin something.

Locker rears will click when going around corners. I've even heard them click sometimes when first pulling out from a stop. So you either have a Detroit Locker or your rear end is broken. I hope it's the former.

Can you describe exactly what you mean when you say "rocking back and forth"?....If you jack up the rear tires and turn them and they turn the same way you have a posi of some sort...If they turn opposite ways you have an open rear end.