C4AW-4025-B part number on the lower left unit, which verifies it as a nodular unit.
The axle housings themselves had many different variations over time as well. These variations include different-size drum brakes, disc brakes, and wheel hub arrangements.
Since these housings were a series of stamped-steel pieces all welded together, there were many different overall lengths, tubes sections, mounting brackets, and even general constructions over the years (see Chapter 5).
The Ford 8.8-inch is very similar to the General Motors (GM) 8⅞-inch, 12-bolt axle. Some differential experts tell you that the Blue Oval engineers copied the 12-bolt design when they came up with the 8.8-inch axle. While the 8.8 is similar to the 12-bolt, it isn’t identical. Interestingly, the Ford axle uses the exact same size of tapered roller bearings as the GM 12-bolt. The Ford version uses larger axle shafts and different lube flow strategy. These axles did have metal axle tags similar to the 9-inch axles but they were slowly phased out as vehicle programs were updated. There are several reasons for this.
Cost and complexity are two. These tags provided information for the service technicians but wasn’t that important for the vehicle assembly plants. The third reason was basic health and safety concerns for the assembly technicians and other employees who handled the axles in the manufacturing and assembly plants. There were many instances of cuts and scratches from the thin steel cuts and scratches from the thin steel tags sticking up on the axles.
The tags were replaced with adhesive labels that are placed around the axle tube near the brake and wheel end. These labels have a specific code that is similar to the axle code on the 9-inch axles.
This is an example of the brakes that fit the small wheel end bearing for a 10 x 2-inch-wide drum brake on the left and a 10 x 1¾-inch on the right.
Axle Flange Sizes
The chart above summarizes the three flange-style dimensions for currently available units. The large bearing flange can have any of the three sizes of clearance holes listed. The 3/8-inch holes were found on the 1978–1979 model year pick-up trucks, Broncos, and some Lincoln Versailles; the 1/2-inch clearance hole is the most common; and the 7/16-inch hole is extremely rare.
The diagram at left shows the typical wheel-end flange configuration. There are various different outside shapes. Some have a D-shape, full circles, and two flats, and while others have five holes instead of four.
Here is an example of 11 x 2¼-inch drums brakes with the small bearing size on the left and the large Torino style on the right.
The Ford 8.8-inch axle has the same ring gear mounting distance (see Chapter 7) for all ratios, just like the 9-inch. So again, unlike the GM and Dana axles that require a unique differential with different ratios, the Ford 8.8-inch differential is common across all of the ring-and-pinion ratios. There is a ton of aftermarket support for this axle (see Chapters 3 and 4 for more details).
The large bearing size was available with five different brake drum widths. Four of the 11-inch-diameter versions are pictured: 1¾ inches (top left), 2¼ inches (top right), 2½ inches (bottom left), and 3 inches (bottom right). A 2-inch version is not shown.
The 8.8 is a traditional semi-float Salisbury axle with C-washers for axle retention. Many people prefer to just call it the Ford 9-inch-style wheel end. But to be correct, it is a 3/4 float. There are 8.5-inch gears installed in these housings for lower-power vehicle applications. The typical 3-inch-diameter tubes can be a bit flimsy in higher-power applications.
Along with the many different brake and wheel end varieties, many different styles of axle shaft ends were manufactured. Some have only one access hole for the backing plate bolts, while others have three. Most have the two driving holes for the manufacturing process while one has a more square looking drive end. None of which changes the strength of the axle shaft. There are even different drum brake registers.
The Lincoln Continental style of disc brakes use 11½-inch rotors. In the 1980s and 1990s, the Lincoln Versailles brakes and complete axles were highly sought after because it was the only way to get a 9-inch axle with discs in a 58-inch-wide axle package. At this width, many were used in street rod applications without modification. With so many better performing aftermarket options today, there is no reason to use these marginal brakes.
This is an example of the only Ford 9-inch version that utilized one-piece tubes. Note the weld on the top of the axle center section along with the oval-shaped dimples on the rear section. The tubes do not have any welds, and you just see the witness marks of the parting line for the dies on the tubes. This was offered on the 1960 F-100 truck.
The Mustang Shelby GT housing is an easy one to spot, albeit rare, because it has extreme tapering of the axle tubes at the ends. There was a desire to have the stronger, larger tubes near the center of the axle but still retain the narrower tube ends for the wheel ends and the unique Shelby suspension brackets.
Some axle shafts can be shortened and a new spline machined in place. The 28-tooth axle shafts are typically tapered and cannot be shortened. Most 1972 and earlier 31-tooth spline shafts can be shortened and
