Icahn -- who is a now the second leading Navistar shareholder -- also took a near 10% stake in truck maker Oshkosh (OSK - Get Report) last June, in an activist investment that comes amid falling government orders for trucks, fire engines and military vehicles. So far, Icahn's big rig play has performed poorly as he's struggled to get both truck makers to consolidate or induce drastic change.
Navistar is one of the nation's largest commercial truck makers while Oshkosh is the leading U.S. military truck maker.
Icahn's trucks bet has so far been hit by continued weakness in government and military vehicle orders, is expected to continue to weigh on earnings.
In late 2011, Icahn settled an activist push to nominate hostile directors to Navistar's board after the company said that the billionaire could put his directors up for election this year.To be seen is whether MHR and Icahn or a strategic bidder will launch hostile takeover bids for Navistar. Recently Icahn's worked with activist investor Southeastern Asset Management on a newly launched investment in struggling gas giant Chesapeake Energy (CHK), in a move that has already precipitated investor representation on the company's board and billions in asset sales . For more on Icahn's Chesapeake Energy bet, see 5 ways Chesapeake Energy can be