TRY CLEANING THE OUTSIDE UP, AND YOU MAY SEE A ROUND BOLT TYPE HEAD THAT HAS OIL STAMPED ON TOP OF IT. THIS WOULD BE THE FILL HOLE. I THINK YOU MAY HAVE TO LOOK AT PUMP FROM TOP VIEW , LOOKING DOWN AT IT. IF THERE IS NO DIP STICK THEN IT WILL DRAIN BY IT SELF, BUT IF THERE IS A DIP STICK THEN I THINK THE DRAIN SCREW IS ON RIGHT SIDE.