The present specification provides a rear window assembly for a vehicle having a window frame, at least one fixed window panel whose perimeter edge defines a portion of an opening, a movable window panel capable of opening or closing the opening and that is allowed to slidably move past the surface of the fixed window panel, a seal member present on the perimeter surface of at least one of the window panels, and a closure track integrally formed in at least one edge of the window frame. The closure track may force the movable window panel and the fixed window panel closer together, thereby, placing the seal member under compression.