Patent ID: 7933706

Claim:
An automatic transmission comprising: a shift mechanism that executes a shift from a current gear position to a target gear position by engaging or disengaging a plurality of frictional elements selectively; a current thermal load calculating unit which calculates a current thermal load state of the frictional element; a heat generation amount predicting unit which predicts, prior to the start of the shift, a heat generation amount of the frictional element during the shift; a thermal load predicting unit which predicts a thermal load state of the frictional element upon shift completion on the basis of the current thermal load state of the frictional element and the heat generation amount predicted by the heat generation amount predicting unit; and a shift prohibition determining unit which determines whether to permit or prohibit the shift on the basis of the thermal load state upon shift completion predicted by the thermal load predicting unit, wherein the shift prohibition determining unit halts the determination as to whether to permit or prohibit the shift, made on the basis of the predicted thermal load state upon shift completion, when a shift mode of the shift is a second shift mode in which the heat generation amount is smaller than that of a first shift mode.