GM said that in the event of the trucks being struck from behind, the reclining seat backs might move more than allowed by safety regulators and not provide as much protection from injury as designed.
GM said it has gotten no reports of accidents or injury related to this possible defect.
Owners of the new trucks can have the seats inspected and if necessary repaired at GM dealers.
Of the total of 21,721 pickup trucks recalled, 18,972 are in the United States, 2,575 in Canada, 103 in Mexico and 71 outside North America, GM said.
(Reporting by Bernie Woodall; Editing by Gerald E. McCormick)