Image source: Getty Images.Shares of heavy-duty truck manufacturer Oshkosh Corp (NYSE: OSK) dropped as much as 10% on Friday after giving updated guidance to investors. At 3:00 p.m. EDT, shares were still down 9.5% for the day.Management said that 2016 revenue will be $6.1 billion to $6.2 billion and earnings per share will come in at $2.85 to $3.00.