Using a fixed joint to simulate crane

Hi all,
I’m trying to simulate a crane using fixed joints. The user can move the hook of the crane, and when the hook is near the load I move the load in the right position then I crate the joint.
This joint could be broke and recreated many times by pressing a button, but when the joint is recreated again its setup doesn’t match a fixed joint anymore. It behavies like a distance or a spherical joint causing the load rotation along an horizontal plane.
I don’t know why the load is moving like this, have you any suggestions?

Thanks, Andrea