Ford 10.25 & 10.50-Inch Axle Tips - Axle Examination
Fact: This axle received a larger ring gear, which improved its overall strength and addressed the premature failure issues of the 10.25-inch axles when used with 4.10:1 or numerically higher gear ratios. Unfortunately, it was designed with a smaller pinion bearing than its predecessor.
Found under: '99-'05 F-250 and F-350
Weight (lb., approx): 333 (single wheel), 348 (dual wheel)
Ring gear diameter (in.): 10.50
Pinion shaft length (in.): 10.50
Pinion shaft spline count: 31
Axleshaft spline count: 35
Axleshaft diameter (in.): 1.5 (at the splines)
Hypoid offset (in.): 1.50
Gear ratio range: 3.08-7.17
Normal GAW range (lb.): 9,750 (single/dual wheel)
Nominal GCW rating (lb.): 26,000 (single/dual wheel)
Output torque maximum (lb-ft): 10,660 (single/dual wheel)
Output torque continuous (lb-ft): 2,900
Weak points: This axle uses an inner bearing and race that is not as large and strong as the bearing and race used in the 10.25-inch axle. Also, the ring gear is mounted to the carrier using bolts that are non-shouldered and tend to loosen, resulting in the possibility of catastrophic damage to the differential. This is actually a problem that affects both the 10.25- and 10.50-inch Sterling axles.
Fixes: To address the bearing and race issue, you can use the ring-and-pinion from the 2nd-generation 10.25-inch. The trade-off is that you'll get a slightly weaker ring-and-pinion, but you'll get a larger inner bearing and race. To solve the ring-gear bolt problem, replace all of the bolts with shouldered bolts. The technicians at Custom Differentials can set you up with shouldered Dana 70 ring-gear bolts.
Hot tips: If you're short on cash during a rebuild (depending on the ratio you want to use, factory parts for the 10.50-inch Sterling can be almost double the cost of 10.25-inch aftermarket parts), you can use the 2nd-generation 10.25-inch case/carrier and gearset in the 10.50-inch housing (as mentioned above). This can significantly lower your parts bill. Also, a three-spider case/carrier is available instead of a normal two-spider gear case/carrier. This update increases the strength and longevity of the differential because the third-spider gear helps share the load when delivering power to the tires and helps reduce spider-gear wear and failure.
Ford 10.25 & 10.50-Inch Axle Tips - Sterling 1050 - Four Wheeler Magazine
The Sterling 10.5 axle is an automotive axle manufactured by Visteon and is used solely by Ford. It was first used in model year 1985 Ford trucks. The axle was developed to replace the Dana 60 and Dana 70. The Sterling 10.5 axle is currently only made as a full floating axle.
Sterling 10.5 axle - Wikipedia, the free encyclopedia