Sun gears, like part 569-4239, are commonly used in the final drive planetary gear sets.All Cat gears have unique metallurgy compositions tailored to specific applications, with special steel formulas that improve impact resistance and ensure uniformity and proper load transfer. Some Cat gears also undergo proprietary heat treat processes to improve surface, bore, and core hardness. The result is greater durability, which means longer life and better performance.Attributes:• Hardened steel sun gear• Internal Spline Number of Teeth: 21• Spur Gear Number of Teeth: 41• Inside Diameter: 41 mm (1.61 in)• Outside Diameter: 109.7 mm (4.31 in)• Width: 37.5 mm (1.47 in)• Hub Diameter: 60 mm (2.36 in)Application:Consult your owner's manual or contact your local Cat Dealer for more information.