Copyright Goodheart-Willcox Co., Inc. 581 Chapter 17 ∣ Final Drives Harvester Final Drives Cotton pickers, cotton strippers, self-propelled forage harvesters, and combines have unique powertrains. A harvester final drive is mounted on the rigid axle hous- ing. The harvester’s hydrostatic transmission consists of a hydraulic pump and motor that provide the input into a two-speed, three-speed, or four-speed gearbox, which includes a differential. Chapter 7, Manual Transmissions, details a three-speed gearbox, and Chapter 15, Continu- ously Variable Transmissions, details a John Deere two- speed ProDrive gearbox. The transmission’s right and left differential side gears deliver power to the right and left transmission out- put shaft respectively. The machine’s right and left brakes are often mounted to the transmission output shafts. A coupler is used to couple the left transmission’s output shaft to the left driveshaft and another coupler is attached to the end of the left driveshaft to couple the driveshaft to the left final drive. Two couplers and a driveshaft are also used to connect the right transmission output shaft to the right side final drive. Each final drive is mounted to the front rigid axle housing. A Case IH 10, 20, 30, and 240 series flagship combine front axle is shown in Figure 17-14. The transmission is a four-speed countershaft gearbox. Each transmission out- put shaft is splined to its own service brake rotor, which Goodheart-Willcox Publisher Figure 17-12. A simplified drawing of a Caterpillar single- reduction final drive. Stationary hub Track drive sprocket Ring gear Sun gear Reduction planetary carrier Axle shaft Figure 17-13. Double-reduction final drives are used in Caterpillar large dozers. A—Diagram of an elevated sprocket undercarriage double-reduction final drive. B—A Caterpillar D9 dozer with the undercarriage removed, exposing the double- reduction final drive. The drive sprocket segments have been removed from the final drive. A B Stationary hub Track drive sprocket Stationary ring gears Second reduction sun gear Second reduction planetary carrier First reduction planetary carrier First reduction sun gear Axle shaft Goodheart-Willcox Publisher Goodheart-Willcox Publisher