Axle Code
there are various axle code decoders out on the net, including this very site:
http://www.fordtruckenthusiasts.com/.../axlechart.php
some others:
http://www.drivetrain.com/Fordtrkratio_posidata.html
http://hiqties.hypermart.net/9inch.html#idtag
http://www.bronco.com/technical/tabl...e_ratios.shtml
etc...
take them with a grain of salt. you're best bet is to read the code off the id tag on the rear differentia itself. eg: My '82 E350 has axle code 46 on the door jamb sticker, and various decoders would lead me to think it's a 4.56, but the tag on the diff says it's 3.73 and i'm pretty sure it hasn't been swapped...
cheers!



