A plastic window assembly (20) for use in a motor vehicle has a plastic panel (22) and a motor (24). The motor is coupled to a gear and is operable to drive the gear (28) to move the plastic panel in a first panel direction and in a second panel direction. In one variation, the plastic panel has portions forming at least one gear track (36) to define a gear path. In another variation, the window assembly has a frame, and the frame has portions defining a track (150). The track has a central section (156,172) and a terminal section (154, 170), the central and terminal sections intersecting and being non-collinear. In another variation, the plastic window assembly has a flexible strip (136). A first end of the flexible strip is connected to the gear and a second end of the flexible strip is connected to the plastic panel.