Delete WordPress transient under the proper conditions

gistfile1.php

// delete featured coaches transient on coach save
function delete_featured_transient($post_id) {

    // First we want to make sure that this is a real save, not simply an auto save
    if ( !wp_is_post_revision( $post_id ) ) {


	// now we declare our custom content type, because we only want to run this
	// on the save of this type
        $slug = 'coaches';


        // this is where we actually make sure we're on the right type.
        $_POST += array("{$slug}_edit_nonce" => '');
        if ( $slug != $_POST['post_type'] ) {
            return;
        }

	// assuming we're on the proper type, set the transient name
        $transient_name = 'featured_coaches';

	// now delete the actual transient
        delete_transient($transient_name);
    }

// end delete_featured_transient
}
// now we hook that function into save_post and it's all set
add_action('save_post','delete_featured_transient');