Automatic transmission fluid ATF, syringe the resoirvoir out to get the old fluid out then fill with new fluid, do not fill it right up half fill it so there is enough to circulate. Start the car and turn the steering lock to lock to get the air out, once no more air is getting out top up to level on the cap dip stick and replace the cap. Some old fluid will remain in the system but the new fluid will be more than enough to compensate. If you overfill it the excess will be pushed out the vent hole in the cap making a mess.
Dexron III automatic transmission fluid (ATF)
Fuchs Titan ATF 5005 (2 x 1 litre) you will have some left over.