Purchase a bottle of transmission stop leak from your local auto parts store. Find one that is compatible with your make and model vehicle. Some brands are compatible with any transmission type.
Raise the hood of your vehicle, while parked on a flat surface. Parking on a flat surface will let you check the level of the missing transmission fluid.
Pour the entire bottle of stop leak into the transmission fluid reservoir. Make sure you do not over fill it with fluid. If the entire bottle cannot be added, pour enough to replace the missing transmission fluid. If, after adding the stop leak, your transmission fluid level is still low, you will need to add enough transmission fluid to replace what is missing.
Drive vehicle over the next three days, or up to 250 miles, and the stop leak will seal the leak.
Take your vehicle to a mechanic if the leak worsens.
