What kind of smoke are we talking about? is it white or black? You can always check the gear oil level in your transmission, but i doubt that the smoke is ocming from your transmission.

You could have a coolant leak from one of your heater core hoses. that might send some steam up in that direction. is your car overheating at all?

Do you have an sr or a ka-t? cuz then you have turbo oil feed and return lines that could be leaking oil. Is your motor going through a significant amount of oil?