By Terry Kosdrosky, Crain's Detroit BusinessChicago, Illinois--Visteon Corp. is selling its new Chicago assembly and sequencing plant, with its contracts, to privately held Plastech Engineered Products Inc.It's the second major acquisition for Plastech in the past seven months. In February, the Dearborn, Michigan-based supplier bought competitor LDM Technologies Inc. for an estimated $290 million.Plastech would not comment on the Visteon deal, expected to close 30 Sept. Terms were not disclosed.For Visteon, the deal is an unusual move, analysts say. The Chicago plant is part of a supplier park near Ford Motor Co.'s plant. Visteon just started sequencing and shipping parts for key Ford models - the Freestyle crossover vehicle, the Five Hundred and the Mercury Montego. The Five Hundred and the Mercury variant are Ford's replacement for the Taurus, its flagship sedan."Why would they walk away from the systems-integrator role?" asked one analyst familiar with Visteon who asked not to be named. "It doesn't make sense. This is not the kind of thing Visteon wants to sell."Visteon sold the plant just a week after its grand opening. To sell a plant so quickly after investing in property, equipment and people is unusual, analysts said. The 270-employee, 21 500-sq.m plant assembles and sequences front-end modules, cockpit systems, fuel storage systems and climate control systems. Sequencing is where a supplier holds a component, does some assembly, and ships it to an automaker's plant on a just-in-time basis."