....there is a collar that goes on the regulator that binds down on the part that engages the tab of the vent window. This collar keeps the vent from "flapping' or what you may call slop. Also, if the vent wont close all the way due to this slop, you can carefully twist the tab at the bottom of the vent window in the appropriate direction to encourage a better seal-juuust a little so as not to snap it off. You will have to remove the vent window frame and regulator to do all of this. Overall pretty easy-1 hour after panel is off. 10mm socket with extension needed.