1997 Mitsubishi Chariot Old Auto Car 300 000klms On Clock After Short Drive

its an old auto car 300,000klms on the clock . After a short drive when pulling up to a stop,the motor "hunts" ie the revolutions go up and down up and down from 1000 rpm to say 2-3000 rpm also the auto transmission is noisy when engaging gear and there is a fluid sound. I can see no sign of fluid leaking under the vehicle