Ford Sterling 10.5" Axle Rebuild

Custom Diff knows a number of tweaks that help make the Ford 10 1/2-inch more reliable. One is to use shouldered ring-gear bolts from Dana 60 or 70 applications, because they're less likely to loosen over time like the non-shouldered factory bolts. If the bolts loosen, major damage ensues. We also installed a new ABS ring, though our factory ring was fine and could've been reused.

A 40-ton press was used to press on all of the carrier bearings and the pinion bearing. The primary concern here is to make sure the bearings are pressed all the way onto the carrier and pinion.

To enhance longevity, Custom Diff uses the taller pinion bearing and race out of the second-generation 10 1/4-inch Ford axle. Here you can see the taller bearing and race (pictured on the right) compared to the bearing and race found in the 10 1/2-inch axle (on the left).

The new pinion races are tapped in until they seat completely. Then the pinion is installed and the preload set.

The axle comes from the factory with cast steel carrier bearing shims. The install kit uses stamped steel shims. Custom Diff prefers to use machined steel shims that are stronger and lock together. This simplifies installation and improves longevity.

With the carrier reinstalled with the same carrier bearing shim thickness as stock, the bearing caps are tightened and the gear pattern is checked. Our pattern was actually very close, so only a slight change to shim thickness was required. Once the pattern was set, the new pinion seal and the factory yoke was installed.

The ABS sensor simply reinstalls in its mount. As long as there's nothing wrong with it, there's no reason to replace it.

We ditched the factory diff cover in favor of a Genuine Gear G2 cover. This cover is cast from proprietary lightweight aluminum alloy to dissipate heat, it has reinforcing ribs for added rigidity and strength, is heat-treated and shot-peened to handle direct impact, and it has a fully machined seal surface for leak-free installation.

Black RTV silicone adhesive sealant was used to between the G2 diff cover and the axle housing, and then the cover was installed.

Custom Diff inspected our outer wheel bearings and found that they didn't have any play; they felt smooth and the inner oil-bath seals weren't leaking. If there was a problem, Custom Diff has the experience required to remove and replace the bearings and/or inner seals.

The last step was to reinstall the axles. These 10 1/2-inch axles are unique in that they use an O-ring on each axleshaft. This design is less likely to leak when compared to standard gaskets. Our axleshafts and O-rings were fine, so Custom Diff removed the O-rings, cleaned up the mounting surfaces, and then reinstalled the O-rings. It's also important to note that like the ring gear bolts, the axle mounting bolts are a non-shouldered design, and they can loosen over time. A good upgrade is to install shouldered bolts.

With that, our freshly rebuilt 10 1/2 was loaded into our project Power Wagon for the trip back to the Midwest Bureau.

The Ford Traction-Lok requires that a friction modifier be added to the gear oil to eliminate clutch chatter.

After adding the gear oil and friction modifier, Custom Diff recommends that the axle be tilted in each direction for about 20 minutes. This ensures that the wheel bearings are adequately lubed. When it comes to axle break-in, heat is the enemy. For this reason, Custom Diff recommends five short trips of up to 10 miles with hour-long cooling breaks between each run. After that, they recommend keeping trips under 50 miles for the first 500 miles.