Know Your Rear End From a Hole In The Ground

Anybody good with knowing the id #'s on rear diffs.?
With the bed off of my '57 Effie, I've been trying to figure out what kinda diff the prev. owner put in it. 10 bolts facing towards the driveline (no bolts on the rear bumper end). It's got some grid lines like on a Locker, and I noticed the driveline angles slightly to the right, when you look at it from the back.
The code on its inside casing is D2VW-A
Anyone know what that means? Am wishing my digi worked, I'd go out and snap a photo write now for you.
Thanks for any help!

 

D2 number should be a Ford 1972 or later, lots of info, look up NINE INCH FORD, might tell you sumthin....OLDBEET

 

1957 was the first year Ford used the 9" across the entire product line. All of the trucks had them unless you ordered it with the Dana 40, the 3/4 and 1 ton trucks got the Dana 60s.

This guys website has some great information on identifying what you have, 9" Ford stuff

 

Welp, lessee here. A 56 F-100 should still have a Dana but I believe they started using a 9 inch in the 57 pickups, as they did on the pallenger cars....but your description of all the ribbing makes me wonder if someone may have substituted an 8 inch into the truck...here's how ya tell. If the wheel bolt pattern is the old ford pickup 5 on 5.5", you should have a 9 inch. If the wheel bolt pattern is 5 on 4.5", it'll be a passenger car unit and may be the 8"....