One of those questions marks, Kullman said, is the budget showdown in Washington. House Republicans have scheduled a vote for tomorrow to raise the debt ceiling for nearly four months, shifting their attention to pushing through spending cuts.
(Read More: House to Vote on 'No Budget, No Pay' Wednesday)
"If there's a time frame and time line and they can make real progress, that's positive." But Kullman warned against extending the deadline much further. "That just continues the uncertainty."
Besides the U.S. debt and deficit issues, Kullman said China poses another large hurdle to stronger global economic growth. She said it remained to be seen how Beijing would navigate the final stages of the transfer of power there.
"When we take a look at 2013, we have factored in a lower growth environment on average," she said. "But we also factored in an improving environment."
Kullman pointed to two areas of expected strength. "The U.S. in construction is set-up to have a stronger first half than we thought." Additionally, she added, "2013 is shaping up to be another strong year in agriculture."
Agriculture sales rose 18 percent in the fourth quarter, helping to power the company's earnings.
In its automotive segment, however, Kullman struck yet another note of caution. "The growth in the first half in the U.S. is not going to be as strong."
—By CNBC's Matthew J. Belvedere; Follow him on Twitter @Matt_SquawkCNBC