9" Ford rear end question

Hi everyone, I went to a local pull-a-part, to see if I could find any 9" rear ends. I believe I found two. One is in a '84 F-150, I'm not quite sure what they look like but I am pretty sure they are 9". When I turned the tire, both sides turned. The other rear end is out of a '85 F-150 and it looks exactly as the first one I seen. When I turned that tire, the other side didn't spin as the other side did. Also I found a '78 LTD does that have a 9" rear end? What are the odds of the '84 F-150 being a 9"? If I takle a pic of it will you guys be able to tell?

Thanks

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).

There are several good sites out there with an abundance of info about 9" diffs over the years - https://www.google.com/#sclient=psy-...w=1280&bih=664 One easy way to tell is the bottom nuts on that retain the pumpkin. If you cannot get a deep socket on the bottom nuts and have to use a wrench it's a 9".

Here's an earlier post that covered this, too - http://www.clubhotrod.com/shop-talk/...-ford-9-a.html