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Ford Sterling 10.5" Axle Rebuild

Our 210,000-Mile Ford 10 1/2-Inch Axle Gets A New Lease On Life

Ken BrubakerPhotographer, Writer

There wasn't any particular thump, grind, or clunk that triggered our desire to rebuild the rear 10 1/2-inch axle in our "Workin' Dog" '99 Power Stroke-powered Ford Super Duty. Instead, it was the 210,000 miles on the truck's odometer that made us nervous. The truck is in use almost constantly for business, so if the rear axle failed, the result would be unplanned downtime, which is not a good thing.

We turned to the Naeger brothers at Custom Differentials in Bloomsdale, Missouri. Jeremy, a former Top Truck Challenge champion, and his brother Patrick are axle gurus with 37 years of combined axle experience. Custom Differentials specializes in everything from basic rebuilds to the most extreme custom builds. They can either remove and repair your axle in their fully equipped shop, or you can remove the axle yourself (like we did) and bring it to them for service.

When it came to parts, we contacted the folks at Drivetrain Warehouse. They've been around since 1962 and their product portfolio is incredible. They carry installation kits, gearsets, general replacement parts, limited-slip and locking differentials, hubs, axleshafts, gaskets, and so on, from a number of manufacturers. The beauty of this is that with one call you can get everything needed to rebuild or upgrade an axle.

How did the rebuild go? What did we find in our high-mileage axle? What tricks did we learn from Custom Differentials? Read on.

About The Ford 10 1/2-inch
The 10 1/2-inch (commonly referred to as the "Sterling 10 1/2") is a full-float axle with disc brakes found in 1999-2010 Ford Super Duty F-250 and Super Duty F-350 trucks. It weighs in at approximately 333 pounds in single rear-wheel versions. The ring gear diameter and pinion shaft length are both 10 1/2 inches. It has a pinion shaft spline count of 31 and an axleshaft spline count of 35. Compared to its predecessors, the first- and second-generation 10 1/4-inch axles, the 10 1/2-inch axle obviously has a larger ring gear, which improved its overall strength and addressed the premature failure issues of the of the 10 1/4-inch axles when used with 4.10:1 or numerically higher gear ratios. There are a number of limited-slip and locker options available, and there are even aftermarket axleshafts available.

Bottom Line
We now have the peace of mind knowing that unless we do something stupid, our axle will provide years of trouble-free service. Best of all, we chose the downtime for our truck. We hate surprises, and sitting on the side of the road with a blown axle isn't good for the blood pressure or the wallet. Since the rebuild, we've been piling the miles on our truck, and the Traction-Lok has exceeded our expectations. It has provided the added traction our Power Stroke-powered rig dearly needed, and its operation is seamless and chatter-free. We're also digging the beefiness of the Genuine Gear G2 diff cover; it has contributed to cooler diff temperatures.