General Motors is making news in Michigan this week. The Detroit automaker is planning a $40-million investment at its transmission plant in Warren to build the new drivetrain for the next generation of the Chevrolet Volt. The announcement is the latest in a string of high-profile plans G-M has unveiled this year. Those include assembly plant expansions in the Lansing area.Current State talks with Emily Lawler, who covers business news for MLive.com.