I have a 1991 Corolla that has developed a leak behind the dashboard, above the steering column, dripping onto the brake pedal. I read elsewhere that it might be the speedometer cable backing up due to a blocked air vent on the transmission. Is this possible? If so, where is the air vent on the transmission? And is this transmission fluid that is coming back up the cable? It smells burnt inside the car, so I wonder if I might have tranny trouble down the line. Thanks for any help you can provide.