GEAR SHIFT CONTROL DEVICE FOR AUTOMATIC TRANSMISSION

摘要

PURPOSE: To improve durability of a friction element fastened by a gear shift through monitoring of a gear ratio during failure in operation of a means to provide information related to a gear ratio, in a gear shift control device for an automatic transmission having a transient oil pressure control means to effect control of a transient shift oil pressure through monitoring of a gear ratio during the gear shift. CONSTITUTION: A gear shift control device for an automatic transmission comprises a trouble deciding means (i) to decide whether at least one of the number of revolutions of input shaft detecting means (b), the number of revolutions of output shaft detecting means (c), and a gear ratio computing means (g); and a means (j) to cope with failure in operation to suspend control of an oil pressure by a transient oil pressure control means (h) during decision of a failure in operation and prohibit a gear shift to a maximum shift speed or a minimum shift speed by a gear shift control means (f).