If you look closely at the joint check you should see a small pin (using left side as example) to the right of the joint check. This pin has to be driven out as it holds the joint check in.
Sometimes it was filed and polished so well you cannot see it and then have to put some type of coloring agent to let it seep around the pin.


After you have driven the pin out rotate joint check to position seen in photo. This will bring the part that pushes against the extractor to the top where there is no slot (you will see the slot inside once you get the joint check out) Don't loose the spring. It has to be put back in the same way after you compress the spring and it will let it slide inside the hole.
Don't rotate the joint check until you put the pin back in or else the part that pushes the extractor will go into the extractor hole and then has to be compressed to rotate it.