Tillers

I BOUGHT A HUSQVARNA TILLER LAST FRIDAY MODEL #DRT900H I DON'T THINK IT HAD ANY GREASE IN THE GEAR CASE ALL I COULD FIND ON GREASING THE GEAR CASE WAS 1 OUNCE A YEAR AFTER I RUN THE TILLER FOR ABOUT 15 MINUTES THE GEAR BOX WAS SMOKING.I WOULD LIKE TO KNOW HOW MUCH GREASE I NEED TO PUT IN THE GEAR CASE IF IT WAS EMPTY. IF NOT EMPTY OF GREASE WHY DOES IT GET SO HOT?