my car has a transmission leak

Low fluid level in a transmission can cause serious damage if in doubt tow your car to a repair shop. If you want to see what the repair involves you need to look at a manual and identify the source of the leak. Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info or there is a company that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You can get a one week subscription or year subscription very cheap. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have ,much better than generic workshop manuals from parts stores, much cheaper than the factory manual try http://bit.ly/mitchell_repair_manuals_online and get an online repair manual subscription. Its impossible to guess without being able to see the leak first hand.