U.S. automotive parts maker Visteon Corp has signed a preliminary deal to sell all of its stake in South Korean unit Halla Visteon Climate Control Corp, according to reports in local media, sending Halla Visteon shares sliding to their lowest levels in over six months. One paper, Korea Economic Daily, said on Monday Visteon plans to sign a final deal to sell its 69.99 percent stake in Halla Visteon to South Korean private equity firm Hahn & Company next month.