A transmission (8) having a transmission housing (26) having a region in which gear wheels (66, 68) rotate and a heat exchanger (30) which absorbs the heat generated in the transmission (8). This heat is transferred to a transmission lubricant and released to a coolant to transport the heat away from the transmission (8). A recess (56) is provided, in the transmission housing (26) outside of the region in which the gearwheels (66, 68) rotate, through which transmission lubricant flows and in which the heat exchanger (30) is arranged. The heat exchanger (30) has a bypass valve (48) which enables the heat exchanger (30) to be bypassed starting at a predefined low or excess pressure.