Framed Partition Glass and Division Sash Construction
Unlike the frameless side windows found on older iterations of this sedan, the 2015 to 2019 doors are built with rigid steel door frames that house fixed triangular partition windows alongside the drop glass. On each door, a vertical metal division bar—designated by Subaru as the door glass sash—stands between the roll-down window and the stationary vent glass. The green-tinted tempered glass does not feature antenna grids, defrosters, or integrated electronics; instead, it relies entirely on its surrounding partition rubber weatherstrip and mechanical anchors to stay sealed against road spray and wind.
Securing the sash requires working inside the door cavity. While an exterior #2 Phillips screw holds the top edge within the upper frame, the lower foot of the division bar bolts directly to the inner structure with two 10mm hex fasteners. Accessing those lower bolts involves stripping the interior door trim card, removing the door speaker, and peeling away the vapor barrier. Because the glass run channel integrates directly with the partition seal, the main door glass must be unbolted from the regulator and tilted out of position before the sash and stationary pane can be maneuvered free.
Addressing Highway Flutter and Factory Service Updates
Owners of early 2015 and 2016 models frequently experience a distinct rushing air or fluttering noise right at the front partition joint when traveling at highway speeds. Subaru documented this issue thoroughly in Technical Service Bulletin 12-176-14R for the front doors, followed by TSB 12-177-14 for the rear vent sections. The factory remedy showed that standard glass placement alone was inadequate without supplementary sealing: it called for redesigned division sashes, revised rubber channels, specialized EPT foam pads, and a specific 320mm strip of butyl tape applied behind the triangular seal to close the aerodynamic void.
Production line updates corrected these wind paths starting in late 2014 for rear doors and September 2015 for front doors. When I handle this repair at your driveway or office parking spot across the Greater Toronto Area, ensuring these partition seals and butyl barriers seat without pinching is the difference between a silent cabin and an intolerable buffeting sound on the 401. Whether servicing a base 2.5i, Sport, or a 3.6R Limited, the door frame tolerances leave no margin for a folded weatherstrip lip.
Front Versus Rear Vent Assemblies and Component Differences
The front and rear doors handle their stationary panes differently despite looking similar from the outside. The front door setup corresponds to dealer service kit numbers 61099AL00A for the passenger side and 61099AL01A for the driver side. Up front, the glass shape is dictated by the mirror base triangle, meaning the sash must align perfectly with the exterior mirror gusset to keep water from tracking past the run channel. If the sash angle shifts by even a millimeter during reassembly, the roll-down glass will bind inside the division channel on its way up.
In the rear doors, the vent glass assembly corresponds to factory reference numbers 62099AL00A on the right and 62099AL01A on the left. The rear quarter panes taper sharply toward the C-pillar frame, sitting directly over the wheel arch stamping. Because the rear division sash extends down into a narrower section of the door shell, maneuvering the glass and its captive perimeter molding out from between the door skins requires releasing the rear lower glass guide entirely, ensuring the drop glass remains protected while clearing the inner structural pinch points.
