GM 10-bolt
Unfairly, this axle has been the redheaded stepchild in the family of GM axles. Why is this unfair? Because it boasts an inner pinion bearing that is stronger than the one found in a 12-bolt axle, and the pinion-shaft diameter is also larger. Before you run out and snag a 10-bolt, though, be aware that GM offers seven different variations of this axle.
Applications: Front and rear.
Type: Semi-floating.
Spline count: 28 and 30.
Factory ratios: 2.56:1 through 4.56:1.
Maximum tire size for stock axle: 35-inch.
Strong point: Strong ring-and-pinion for its size, large ring-gear bolts, spider gears and pinion diameter (when compared to its competition, the Dana 44).
Weak point: Avoid the centrifugal-force-triggered Gov-Lok locker.
Junkyard jewel: Find a 10-bolt-equipped Chevy Blazer or Suburban built after November 1989 through 1991 because it will have 30-spline axleshafts.
Building secrets: The axletubes can spin on the centersection, so notch the housing where the axletube meets the centersection and re-weld.
Aftermarket alternatives: Custom Differentials.