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40 HP Gearbox RW-300-6S, Spline 1-3/8" Input Shaft

Item #87855
With a rated horsepower capacity of 40, this gearbox will provide an excellent operation to your rotary cutter. It has a 6 spline input shaft that measures 1-3/8 in. This rotary gearbox may be used with 4 ft., 5 ft., and 6 ft. rotary cutters.
Product Overview

Gearboxes work to administer a transfer of speed and torque through their internal gear rotation, helping the overall performance of your rotary cutter. This RW-300-6S gearbox operates at 40 HP. The housing is constructed from durable ductile iron and the input shaft measures 1-3/8 in. with 6 splines. It has a beveled type of gear, with the gear ratio measuring 1:1.47. Designed for use with 4 ft., 5 ft., and 6 ft. rotary cutters, this rotary cutter gearbox has 4 bolt holes measuring 5/8 in. on a 6-3/4 in. bolt pattern for installment.


  • Gearbox RW-300-6S
  • Horsepower Range of 35 to 45
  • Max RPM 540
  • For 4ft., 5ft., and 6 ft. rotary cutters
  • Housing construction: Ductile iron
  • 6 spline Input shaft: 1-3/8 in.
  • Gear ratio: 1:1.47
  • Gear type: Bevel gear
  • Bolt holes: 4, with 5/8 in. diameter
  • Bolt pattern: 6-3/4 in.
  • Output shaft 1-1/2 inch X 12 Spline
  • Length of output shaft 4-1/2"
  • Length of input shaft 3-7/8 inch X 1-3/8 inch diameter 6 spline
  • Beveled internal gears
  • 4 Bolt Mounting Holes that measure 5/8 inches in diameter
  • Bolt Pattern 6-3/4 inches
  • For castle nut use ASC # 102241 - 1" Castle Nut
  • For output shaft gearbox seal RW300 use # 89757
  • For input shaft gearbox seal RW300 use #89756
  • For blade hub use #89754
  • After the pan and blades are installed onto the gearbox make sure when blades are turned back toward the gearbox shaft they do not hit the shaft or nut but clear it before using the rotary cutter.

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