In the gear shaving process, the work gear's tooth flank can be crowned longitudinally by varying the plunging of the shaving cutter. This method, however, produces a low accuracy profile and low crowning flexibility. Hence, in this study, we propose a mathematical model of a parallel shaving process that uses an auxiliary crowning mechanism for longitudinal gear crowning, which improves the accuracy of the work gear profile and the flexibility of the crowning process. We also investigate the effects of the shaving cutter's assembly errors on the longitudinal crowning process using gear tooth flank's surface topology, contact ellipses, and transmission errors to identify the sensitive kinematic errors generated by assembly errors in the work gear pair. Two numeral examples are presented to demonstrate the merits of the proposed gear shaving methodology for longitudinal gear crowning. (C) 2014 Elsevier Ltd. All rights reserved.