There are several different posi options for the Dana 44 thanks to it's use in Jeep CJ's and early Ford Bronkos and not hard to find. You can even get a Detroit Locker for a Dana 44.

Tom

What?

Yes I've seen many options. I think the 44 is used as the front diff.

Yet I was just trying to work out what the diff is that is in the bird at present. Which you can see in the photo.

What we used to do with the 9", was to machine a provision for a second pinion shaft with in the differential and fit a second set of
pinion gears. As Ford did, 4 pin and 2 Pin diff. This made the diff much stronger. Perhaps I can do this to the shoe box diff.

There's no doubt the 9" has the best Posi-lock (Limited Slip Differential). Yet has anyone experienced "Eatons True-trac"

So I have found a 9" diff out of a 57' Tbird.And wondering if the internals are interchangable with current 9".
Are they strong axles as some variations have been over the years?
What ratio can I expect it to be?

Any guidance here???

Later 9 inch carriers will go into ’57 housing, but my experience is that some grinding of the ’57 housing will be necessary to have the later pig go into the opening.

While referred to as being a ‘9 inch’, my understanding is that the original ’57 ‘Bird ring gear size was actually 8.75 inch.

My books show:

• the original ’57 ‘Bird axle shaft spline count was 28

• original ’57 ‘Bird rear end ratios were:

- 3.56 for the 3 speed B-W 259 transmission

- 3.70 for the B-W T-85 3 speed with overdrive

- 3.10 for the Fordomatic

Hope this helps.

NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

That does help, thanks.

A set of 488s went right into my 57 Bird housing with no grinding required.

I believe 411s were also an original option for an O.D. tranny in 57.I have seen a few 57 Birds with that setup

Oldmics

By the way isn't the rear axle assemble in a 55/56 Bird considered a Dana 46?

4.88s! GooD GrieF, JH!

Put another way... WoW!

NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York