Pictures would be great! A 9" Ford is a 'front loading' differential, meaning the center section (3rd member) is removable keeping the gears and the carrier assembled as a unit. Reason all the racers like it as that you can have as many center sections as you want set up with different gear ratios, spool, posi, or whatever and you're able to change the gears just by popping the axles out and changing the center section...

If the differential has a removable cover on the back, it's not a 9". (though some 9" Fords have been modded to add a removable rear cover, too..but never from the factory).