Provides a business analysis of Navistar International Corp., Minneapolis, Minnesota-based holding company engaged in the manufacture and distribution of trucks, busses and engines, focusing on its strengths, weaknesses, opportunities for improvement and threats to the company. Strengths, including market leadership in heavy truck production, extensive distribution network, and relationship with Ford Motor Co.; Weaknesses, including heavy start-up costs for two engines, lag in the incremental gross margins, and lawsuit by Caterpillar Inc.; Opportunities for improvement, including increase in heavy-truck demand, growth in popularity of diesel engines, and international expansion; Threats to the company, including strong competition in the medium sized truck market, supply chain shortages, and incremental steel prices.