Patent ID: 8370036

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 shift control unit which performs the shift in a first shift mode; a current thermal load calculating unit which calculates a current thermal load state of a frictional element; a first heat generation amount predicting unit which predicts, prior to start of the shift, a heat generation amount of the frictional element if the shift is performed in the first shift mode; and a first thermal load predicting unit which predicts a thermal load state of the frictional element upon shift completion if the shift is performed in the first shift mode on a basis of the current thermal load state of the frictional element and the heat generation amount predicted by the first heat generation amount predicting unit, wherein the shift control unit either performs the shift in a second shift mode, in which a heat generation amount is lower than that of the first shift mode, or prohibits the shift when the thermal load state upon shift completion predicted by the first thermal load predicting unit is inside a predetermined region.