Dimensional Variation Analysis (DVA) is a decision-making methodology for tolerance analysis, and is employed to evaluate assembly variations and identify problems in manufacturing assembly processes at early stages of design. In this study, the impact of component tolerances on manufacturing and assembly process variations is presented on a case study. The case study includes the alignment analysis between crankshaft and input shaft for clutch systems. The impact of component tolerances on axial alignment measurements in regard to these applications is discussed. The study shows that when combined with effective tolerance combinations, Variation Simulation Analysis (VSA) facilitates operational visibility; thus improve quality, reduce manufacturing cost, and enable reduction of production release time. The case study presents the impact of component tolerances at two levels: 1. Pre-Design, 2. Optimized Design.