Shareholders of Oshkosh Corp. on Friday dealt a setback to Carl Icahn, defeating at least five of six candidates the activist investor nominated for the truckmaker's board of directors.

The Oshkosh, Wis.-based company in a statement said that based on preliminary estimates at least 12 of the 13 candidates supported by the current board had been elected, with one race too close to call. Oshkosh said it was still compiling an official vote count and expects to report the results of the final election within four business days.

Icahn, who holds just under 10% of the company's shares, had been pushing Oshkosh to consider a link up with rival Navistar International Corp. and find a buyer for its $3 billion-sales JLG Industries aerial lift business. The investor received the backing of Institutional Shareholder Services Inc. in his proxy contest, but apparently failed to win over a majority of shareholders.

The company in a statement said that over the past several weeks, "we have had the opportunity to engage in productive and informative discussions with many Oshkosh shareholders," adding that the board and management team "remain focused on delivering value to all of our shareholders and continuing the progress we have made towards building a stronger future for Oshkosh."

Icahn's next move at Oshkosh is unclear. The investor has an agreement with Navistar, where he also holds about 10% of shares outstanding, not to wage a proxy fight in return for the company pledging to hold a shareholder vote that could eliminate its staggered board.

Executives at Warrenville, Ill.-based Navistar have said they see the rational of working with Oshkosh.

Icahn has hit a rough patch of late. The investor earlier this month walked away from his $1.73 billion hostile bid for Commercial Metals Co. after failing to win sufficient support among the metal recycler's shareholders. Last year he withdrew a similar offer to acquire Clorox Co. after his bid was rejected by the company and no higher offer emerged, and also made unsuccessful runs at Dynegy Inc. and Mentor Graphics Corp.