Sterling 10½-inch
This axle debuted in the early '80s in ¾- and 1-ton Ford pickups and vans, including dualies. Their popularity with builders took awhile to grow, due to the slow availability of aftermarket gears and parts. One of the reasons was that most Sterling axles manufactured after '87 used ABS senders in the differentials, which limited their upgradeability. One of the neat things about Sterling axles is the unique O-ring design on the axleshafts, which are less likely to leak when compared to standard gaskets.
Application: Rear.
Type: Full-floater.
Spline count: 35.
Factory ratios: 3.08:1 through 4.10:1.
Maximum tire size for stock axles: 44-inch.
Strong point: Large teeth on ring-and-pinion, mass availability.
Weak point: Ring-gear bolts tend to loosen.
Junkyard jewel: Use an axle out of a '99-or-newer Ford truck because they sported disc brakes.
Building secrets: The stock ring-gear bolts are notorious for loosening due to their design, which omits a shoulder on the bolts. Custom Differentials uses Dana 70 ring-gear bolts, which have shoulders and won't loosen.
Aftermarket alternatives: Custom Differentials.