replace the wp_check_password pluggable function

I’ve been scouring the internet trying to figure out exactly how to replace the wp_check_password function. Reading the comments in the pluggable.php file in the documentation makes me think this should be an easy process but I must be missing something. I’ve created a plug-in called “joomla_check_password” and I added a filter like so:

add_filter(‘check_password’, ‘joomla_check_password’, 3);

But evidently this hook is actually right after the normal wp_check_password function is called. The only filter I can find right before the function is called is the authenticate filter, which would mean that I need to replace the wp_authenticate_username_password function as well. Am I correct in saying this?