UPDATE 1-Oshkosh shares up, Navistar down after contract news

* Oshkosh shares surge 25 percent in post-market trading

* Shares of Navistar fall 10 percent

* Action comes after DOD awards $1.1 bln deal to Oshkosh

CHICAGO, June 30 (Reuters) - Shares of Oshkosh Corp (OSK.N) surged in post-market trading on Tuesday after it won a $1.1 billion, fixed-price contract to build armored trucks for U.S. troops in Afghanistan.

OshKosh beat out a number of companies, including Navistar International Corp (NAV.N), for the Pentagon award to build 2,244 of the new Mine Resistant Ambush Protected All Terrain Vehicles (MRAP-ATV).

The award was announced shortly after the close of regular trading on Wall Street.

Oshkosh shares were last trading at $18.22 in after-hours trading, up $3.68, or about 25 percent, from their close of $14.54 on the New York Stock Exchange.

Navistar shares, meanwhile, fell $4.40, or about 10 percent, to $39.20 after closing the regular session at $43.60.

Industry executives have said they expected the Pentagon to urge the winning company to subcontract with one of the losing bidders to produce the trucks faster.

Other bidders included BAE Systems (BAES.L) and Force Dynamics LLC, a joint venture between Force Protection Inc (FRPT.O) and General Dynamics Corp (GD.N).

Defense Secretary Robert Gates is a big fan of the MRAP armored vehicles, which feature a V-shaped hull to deflect roadside bombs.

But earlier versions were not maneuverable enough to deal with Afghanistan's difficult terrain so the Pentagon has been racing to buy a lighter version. (Additional reporting by Andrea Shalal-Esa) (Reporting by James Kelleher; editing by Carol Bishopric)