Everything you've ever wanted to know about Ford 9 Inch Differentials!

9 Inch Pinion Supports

Standard 9" pinion support, D2SW-C

D2AW Pinion Support with guard

While slightly different in appearance, and the absence of a guard on the D2SW-C, both supports use the same inner and outer bearings.

D2AW and D2SW 9" pinion supports, back side.

D10W-4668-A Daytona pinion support (back side)

D10W-4668-A Daytona pinion support (front)
Other standard pinion supports encountered:
WAT B2(on a WAR case),C0AW-A,C6AW-4668-A,C7AW-C(guarded support as well) and a D2SW-4668-C(marked with the 4668).The D2SW-C seems to be the most common encountered through 1979 on the C7AW-E cases I have viewed.

Earlier daytona pinion supports: C5AW-4668-C

Other Ford differentials, similar to the 9"

The 9 1/2" story..
Here is something else you may run across, a 9 3/8" ring gear housing(sometimes called a 9 1/2" Ford carrier),I don't know much about them, but looking in the book they appear to have come in the larger Lincoln and Mercury vehicles.Note casting number C8AW-4668-B on pinion support and the double ribs(spaced further apart) with the end bent down on one.From what I understand parts from these rears do not interchange with the 9 inch carriers.
The Ford 8"

The younger brother to the 9 inch, the Ford 8 inch is an identical design, but on a smaller scale. Generally speaking the 8" will not handle the abuse of the 9", and is good to about 300 lb.ft of torque under high-stress. It can only be fitted with 28 spline axles.

Shown at right is a 1966 and earlier case, with only horizontal ribs and no fill plug. (C20W-4025-F)
Later improved carrier for the 8" found in 67 and up. Note the fill plug in the case, as well as the vertical reinforcement ribs. If you must build an 8" for any amount of abuse, get this case. It can be found in a variety of models up to the late 70's Mustang II's.

Tell the difference between 9" and 8" Axle Housings

Shown above is the typical 1967 and up 9" (lower) and pre-1967 8" housing (upper). Note no fill plug on back of the 67 and up housing, this is true for the 67 and up 8 inch housings too. Earlier housings, like the 65-66 Mustang 8" pictured have the fill plug in the back, this is true for the earlier 9" as well.

One of the ways many people spot a 9" rear end in the car is by looking for the hump in the center of housing, this is not always the best way, as 9" housings made prior to sometime in 1966 do not have the this large center protrusion.The 9" shown above is out of a 63 Galaxie, note its roundish appearance, two dimples and fill plug in housing back.

Here is the 9" housing style familiar to most, note the large center protrusion or simply the "hump" in the middle. Housing also has the two dimples, but note lack of fill plug.This housing is out of an early Bronco.

The little brother to the 9" housing is the 8" housing, note its more oval appearance when compared to the above two 9" housings.This one is out of a 65-66 Mustang, note the two dimples and fill plug.

Another area of concern when swapping axle housings into earlier Mustangs (65-66 models especially) is the diameter of the outer axle tube.Note the taper on this 8" 65-66 Mustang housing, a smaller U bolt and lower shock plate were used originally with these cars.The HIPO 289 cars were the only 65-66 Mustangs to recieve factory 9" axles, the tubes are tapered as well at the end to utilize the same lower shock plate as the regular 65-66 Mustangs.

Notice this axle tube has no taper at end,as is typical for most housings.A typical early Mustang swap is a later Granada housing, were the non-tapered tube can become an installation problem at times.

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