GM product chief Mary Barra will take over as CEO later this month. Her biggest challenge: Shifting GM's revival into high gear. Photo credit: General Motors Co.

General Motors (NYSE:GM) has come a long way since it exited bankruptcy back in 2009. It's solidly profitable, and its latest products are selling well and impressing critics. But much work needs to be done: GM's profits aren't anywhere near those of its closest rivals, and it still hasn't really harnessed the potential of its massive global scale.

Change comes slowly in the auto business, but retiring CEO Dan Akerson did a good job of getting GM rolling in the right direction. Now, with the U.S. government no longer among its shareholders, GM has an opportunity to shift into high gear under its new CEO, Mary Barra.

Much has been made of the fact that Barra is the first woman to lead a global automaker. But Barra proved her mettle by successfully completing what many observers thought would be an impossible task: fixing GM's slow and bloated product-development process. The result has been cars like the Chevy Impala and Cadillac CTS, which have wowed critics and customers alike.

But as she takes the wheel as CEO, Barra faces an even bigger challenge: transforming GM from a promising turnaround story to a global powerhouse. As Fool contributor John Rosevear explains in this video, GM needs to up its game in a big way this year -- and Barra will have to hit the ground running to keep GM's revival on track.