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40 HP Gearbox RW-300, Smooth 1-3/8" Input Shaft

Item #87854
The average rating for this product is 5 out of 5 stars
5 reviews
With a rated horsepower capacity of 40, this gearbox will provide an excellent operation to your rotary cutter. It has a smooth input shaft that measures 1-3/8 inches. This rotary gearbox may be used with 4 foot, 5 foot, and 6 foot rotary cutters.
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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 gearbox operates at 40 HP. The housing is constructed from durable ductile iron and the smooth input shaft measures 1-3/8 inches. It has a beveled type of gear, with the gear ratio measuring 1:1.47. Designed for use with 4 foot, 5 foot, and 6 foot rotary cutters, this rotary cutter gearbox has 4 bolt holes measuring 5/8 inch on a 6-3/4 inch bolt circle for installment.

Specifications

  • Fits many brands of mowers
  • Gearbox RW-300
  • Horsepower: 40
  • Max RPM 540
  • Turns both clockwise or counterclockwise
  • For 4 ft., 5 ft., and 6 ft. rotary cutters
  • Housing construction: Ductile iron
  • Mounting Base Thickness is 3/8 inch
  • 9 inches tall
  • Distance between mounting holes is 4-3/4 inch
  • Smooth input shaft: 1-3/8 in diameter X 3-7/8 inches long
  • Output shaft 1-1/2 inch diameter X 12 Spline being 4-1/2 inch length
  • Spline length is 2-5/8 inches
  • Gear ratio: 1:1.47
  • Gear type: Bevel gear
  • Bolt pattern: (4) 5/8 inch diameter holes on a 6-3/4 inch bolt circle
  • Uses 90 Weight Gear Oil (Not included)
  • The input shaft snap ring comes with this and is located in the plastic tube attached to the shaft
  • 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

Check out our selection of Rotary Mower Parts & Gearboxes

Featured Review
This shopper rated the product 5 out of 5 stars
First one lasted for 15 years, seal finally went out. About to purchase another!

Purchased one of these gear boxes for my second hand, 6 ft. rotary cutter of unknown origin 15 years ago. Was a perfect fit. I check the oil level at start of every mowing season. Couple of days ago I noticed it was a bit noisier than usual. Checked oil again and none. Hard to say if the bearing wear caused the output shaft seal to die or vice versa . Gear backlash is still good and not a lot of play in output shaft. I plan to rebuild it if the gears still look ok but need to get cutter working now so going to buy another. I only use the cutter on average 50 hours a year but I still consider 15 years of use to be pretty good service considering the beating it takes in the rocky ground I have and it sits out all year. — Ferd from KS

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Product Review Summary
Based on 5 reviews
The average rating for this product is 5 out of 5 stars
Overall Rating: 5.0/5.0
Customer Reviews
September 10, 2023
First one lasted for 15 years, seal finally went out. About to purchase another!
This shopper rated the product 5 out of 5 stars

Purchased one of these gear boxes for my second hand, 6 ft. rotary cutter of unknown origin 15 years ago. Was a perfect fit. I check the oil level at start of every mowing season. Couple of days ago I noticed it was a bit noisier than usual. Checked oil again and none. Hard to say if the bearing wear caused the output shaft seal to die or vice versa . Gear backlash is still good and not a lot of play in output shaft. I plan to rebuild it if the gears still look ok but need to get cutter working now so going to buy another. I only use the cutter on average 50 hours a year but I still consider 15 years of use to be pretty good service considering the beating it takes in the rocky ground I have and it sits out all year.

Ferd from KS
August 29, 2023
worked great!
This shopper rated the product 5 out of 5 stars

Was concerned about the bolt pattern but everything lined up perfect! 4 bolts and a shear pin and I was back in action!

Kevin from AL
October 20, 2020
5' King Kutter
This shopper rated the product 5 out of 5 stars

This replacement gearbox worked perfectly on my bush hog.

PirateKevinNC from NC
May 23, 2019
gearbox rw-300
This shopper rated the product 5 out of 5 stars

received it today.installed it on 5 ft. brush hog works great. great price. Works great. Thank you.

Elton Kramer from OR
August 01, 2017
Great Replacement
This shopper rated the product 5 out of 5 stars

Gearbox fit my older Pittsburgh Field General perfect. Box came with new output castle nut which wasnt clear in the description. Dont forget to fill it with 90 weight oil before you run it.

J. Duffy from SC