Best idea is to add 2 or 3 litres of Dexron 3 to the transmission - the fluid goes in thru the fluid level tube which is just to the right of the brake master cylinder. Start with just 2 litres and whilst you are adding it keep looking under the car to see if you can spot where it is draining from. Prime suspects will be the steel cooler lines where they join the transmission, a few loose screws on the pan or the fill tube dislodged. They are the cheap ones. Once you can get enough fluid in her, you can then move it to a spot where you can raise the car on ramps and have a proper look. Good Luck.
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