Open Labyrinth. The 2824029-EXC is identical to the 1102780 (Cold Weather), except it has the Open Protected Labyrinths (or OPLs) which reduces mud packing in muddy ground conditions and in turn improves duo-cone seal life. It will not cause any operational issues to install a 2824029-EXC on a machine originally configured with the 1102780 (Cold Weather) final drive.