Does anyone know how you can tell if a transmission came from Japan or US. I have a b16a in and I need to replace the tranny. I am not sure if it's the original one that came over with the motor, or if someone got one here. It just says S1 and the serial #. I was curious if the USDM transmission I am going to put in it is going to have the same gearing as the one I have now, or if they would be longer??

thanks
Mike