Patent ID: 8465394

Claim:
A method of operating a transmission device ( 10 ) of a vehicle drive-train ( 1 ) that comprises a plurality of frictional shifting elements (A, C to E) and at least one interlocking shifting element (B) for obtaining various gear ratios (“1” to “R”), wherein in a neutral operating condition (“N”) of the transmission device ( 10 ), in which a force flow is interrupted in an area of the transmission device ( 10 ), and in a case of an operating condition variation of the vehicle drive-train ( 1 ) in which, when required to establish the force flow in the transmission device ( 10 ), the at least one interlocking shifting element (B) has to be changed from a disengaged to an engaged operating condition, the method comprising the steps of: increasing transmission capacities of at least two frictional shifting elements (A, C), which have to be engaged to produce the force flow, to a level at which the frictional shifting elements (A, C) operate in a slip-free condition, determining a rotational speed difference (nd_B) in an area of the interlocking shifting element (B), and adjusting a drive torque (m_mot) of a drive machine ( 9 ) to a level that brings the rotational speed difference (nd_B) in the area of the interlocking shifting element (B) to within a predefined speed difference range (nd_Bo, nd_Bu) such that within the predefined speed difference range (nd_Bo, nd_Bu), the interlocking shifting element (B) is in an at least an approximately synchronized condition and can thus be engaged.