USA Standard Gear ZGK2139 Ford 10.5" 3.73 Rear Ring & Pinion Kit with Install Kit & 35 Spline Posi

The USA Standard Gear ZGK2139 is a complete re-gear combo kit for the Ford 10.5" rear differential, bundling a 3.73 ratio ring and pinion gear set, a master install kit, and a 35-spline positraction limited slip differential (LSD) — everything needed for a full differential rebuild or gear ratio change in a single part number.

Ring & Pinion Gear Set:

• Designed for the Ford 10.5" rear differential with a 12-bolt ring gear and 12-bolt rear cover
• 3.73 gear ratio for an ideal balance of towing capability and highway performance
• Engineered to exceed OEM specifications with rigorous in-house dimensional, material, and fitment testing
• Precision-machined using proven manufacturing technologies for quiet, reliable operation
• Standard one-year warranty against manufacturing defects

Master Install Kit Includes:

• Carrier bearings and races
• Pinion bearings and races
• Pinion shims and carrier shims
• Crush sleeve
• Pinion seal and pinion nut
• Ring gear bolts
• Cover gasket
• Marking compound with brush
• Thread locker

35-Spline Positraction Limited Slip Differential:

• Clutch-style limited slip (LSD) positraction unit for improved traction across all terrain types
• High-strength nodular iron case for durability under heavy loads
• Fully rebuildable design for long-term serviceability
• NP 504493 / NP 949481 inner pinion bearing and race included

This combo kit provides a convenient, one-stop solution for re-gearing the Ford 10.5" axle. Professional installation is recommended — differential gear work requires precise setup of backlash, preload, and gear pattern.