Technical 9” Differential Tag

Has anyone seen a tag like this on a 9” ?
It is in a small ford housing. Looks like it is an open 3.00 ratio. Everything else on the tag does not seem to correspond to any of the charts i have been able to find. I was hoping to be able to tell if it is a 28 spline unit.

 

Do you know of the year it was built! You can also look at the ends of the axles and tell if it’s a 28 or 31.








Bones

 

Most everything was 28 spline, 31 was hi-po only

 

I do not.
Axles are the next step. But we are into about a week of rain and no garage.

 

So I'm ok with 28 spline then. All the info I’ve seen seems to point in that direction.

 

31 spline were common in trucks after about 77 or so. I’ve harvested a bunch of N case nine inch rear ends out of my local salvage. They have the 31 spline, usually. In those years, usually you can tell 31 spline by the indentation in the end of the axle..... but as with all Ford stuff.....never say “ always” The odd thing about Ford in those years, while searching for the N cases, I found that they were common in 302 equipped “ sport” models. Never saw one behind a 460!






Bones

 

I’ve read that, for the most part, 28 spline axles have a oblong indent at the wheel mounting end.

 

I'm not positive on this, but IIRC the 31 spline axles all used the large axle bearing, and you did state "small" housing. Don't think they made a small OD brg. with the large ID for 31 spline axles. Somebody please verify this one way or the other

 

Mustang and Torino Cobra Jet and Boss cars, had small bearing 31 spline axles.

 

If you are unfamiliar with this rear end and the axles are already out, I’d pull the third member, count the splines and check it over before installing. Then you would know fir sure. And I never saw an ID tag like that one. You might measure the width of the housing for a clue.






Bones

 

Thanks
Well, its raining now, for the next week. but good idea.