Abstract: A modular sliding window assembly for in a motor vehicle body is provided with a sliding pane subassembly which has a snap-fit with a frame subassembly. The frame subassembly preferably comprises a pair of fixed panes, an upper and lower applique, and an injection molded cover member integrating the fixed panes and the appliques. The sliding pane subassembly preferably comprises a generally horizontal run channel member and at least one glazing pane optionally having a run channel guide affixed to a peripheral edge of the pane. The pane is slidably received in a run channel formed by the run channel member. The horizontal run channel member has a snap-fit attachment preferably to one of the appliques. The appliques can have a flexible flange or the like extending inboard from the injection molded cover member, forming a step ridge or like configuration.