Gooday folks, I was tearing down a old 9" rear diff the other night.
The axle came out of a 1966 F100, or that's where I found it.
The truck had been sitting about 35 years.

When I pulled the third member out, and wiped away all the ancient gear oil that looked like tar😳 I couldn't believe it..
I thought it was a open diff.. But it appears to have a Detroit locker installed, factory? I dunno..

I have since been doing as much reading on the 9" diffs as I can. Just trying to figure out for sure if it's the original axle that came in the old truck, or if it's out of something different?

So here I am on the Ford forum, wondering if anyone here knows something about what I might have.

This is the info I have.

Axle tag.= WDM A L
4.11 14S

Third member casting = cwar B 4025

On the inside of the third member
Casting 5F12

And it appears to have a Daytona support, 3" axle tubes, big bearing outers.
And 28 spline axels, and Detroit locker.

Be better if it had 31 spline shafts, but I'm happy about the locker and it was all purchased for 100$

I would add pics if I knew how.

From what I read only the N cases had a factory Daytona support. And a factory Detroit is rare from what I understand..
Strange to find it in a 2wd F100 with a straight six engine.

Thanks to all who may have a bit of info on these old axels.

👍