Still, in January, Oshkosh said that it would respond to investor concerns with "urgency," even after an Icahn slate of directors was voted down by shareholders. Recently, Icahn's had more success with struggling gas giant Chesapeake Energy ( CHK ), as a recent activist push has already precipitated investor representation on the company's board and a $4 billion Friday pipeline sale. For more on Icahn's Chesapeake Energy bet, see 5 ways Chesapeake Energy can be saved from itself. See Carl Icahn's investment portfolio for more on the activists stock picks. -- Written by Antoine Gara in New York