American Truck MAK Differential Helical .5 Ratio 16Teeth Model 21016180 56KH470 808153 New Condition

MAK Differential Helical Gear — 0.5 Ratio 16-Tooth for American Truck Drive Axles (Models 21016180, 56KH470, 808153)

This MAK differential helical gear set is designed for American heavy-duty truck drive axles, featuring a 0.5:1 ratio with 16 teeth on the helical pinion. Unlike standard straight-cut differential gears that produce significant whine at highway speeds, this helical-cut design uses angled tooth engagement to distribute load progressively across the gear face, reducing operating noise by approximately 6-8 dB compared to equivalent straight-cut gears at 65 mph. The 0.5 ratio configuration is specifically intended for high-speed highway applications where the driveshaft turns at half the axle speed — making it ideal for long-haul trucks that spend the majority of operating hours at sustained highway speeds. Compatible OEM cross-references include 21016180, 56KH470, and 808153. This is a differential internal gear set, not to be confused with the ring-and-pinion final drive assembly; it operates inside the differential carrier to allow wheel speed differentiation during cornering while maintaining equal torque distribution to both axle shafts.

Installing a helical differential gear set requires precise backlash and contact pattern setup — the tooth profile is less forgiving of misalignment than straight-cut gears due to the angled contact surface. The critical specification is the pinion-to-side-gear backlash, which must be set to 0.006-0.010 inches (0.15-0.25mm) using a dial indicator. Running backlash tighter than 0.006″ will cause helical thrust loading to push the gear faces together, generating excessive heat and potential galling within the first 500 miles. Conversely, backlash exceeding 0.012″ produces a distinct rhythmic “chuckle” noise during deceleration as the gear teeth slap against each other. Always replace the differential side bearing preload spacers when installing a new gear set — reusing worn spacers will result in incorrect carrier bearing preload and accelerate both gear and bearing wear. Common failure indicators: a whining noise that changes pitch with vehicle speed but NOT with gear selection (differential gear wear), metal flakes visible in the differential oil with a silver-gray appearance (helical tooth surface spalling), and axle shaft end-play exceeding 0.020″ (indicating side gear thrust washer failure).

This MAK differential helical gear set fits American truck drive axles specifying OEM numbers 21016180, 56KH470, or 808153. Always cross-reference your axle identification tag and differential carrier casting number before ordering — similar-looking gear sets from different axle manufacturers (Rockwell, Eaton, Dana) have incompatible tooth profiles despite sharing the same tooth count. For additional truck drivetrain components including ring-and-pinion sets, differential carriers, and axle shafts, contact our sales team with your part numbers. For OEM technical specifications, visit the MAK Official Website.

Technical Specifications

• OEM Part Numbers: 21016180, 56KH470, 808153
• Gear Type: Helical Differential Gear Set
• Ratio: 0.5:1
• Tooth Count: 16 Teeth (Helical Pinion)
• Application: American Heavy-Duty Truck Drive Axles
• Backlash Specification: 0.006-0.010″ (0.15-0.25mm)

Compatible OEM Cross-References

Each gear set is inspected for tooth profile accuracy and surface finish before shipment, packed in rust-preventive oiled paper and corrugated carton, and ships within 1-2 business days. We offer a 12-month warranty against manufacturing defects. For bulk pricing or other truck drivetrain components, contact our team with your OEM numbers. Browse our Forklift Mechanic Transmission section for related drivetrain parts.