King Kutter 40HP Gear Box Parts

Replacement 40HP gearbox parts and complete gearbox assemblies for King Kutter rotary cutters and finish mowers, covering shear pin and slip clutch drive setups across XB Series, Flex Hitch, and standard models.

Fits Models At A Glance

• Rotary Cutters: 4', 5', 5.5', 6' rotary cutters
• XB Series: XB Series 48 inch rotary mower
• Finish Mowers: 4', 5', 6', 7' finish mowers
• Flex Hitch: 4', 5', 6' Flex Hitch finish mowers

Key Notes

• Application: 40HP rated gearboxes for cutters, mowers and tillers
• Drive types: Shear pin and slip clutch input configurations
• Coverage: Complete gearbox assemblies plus internal service parts
• Service parts: Bearings, seals, gaskets, gears, shafts, caps and plugs

Why Choose Broken Tractor

• ✅ Full 40HP gearbox coverage from assemblies to seals
• ✅ Both shear pin and slip clutch parts available
• ✅ Fast shipping from two US locations

Frequently Asked Questions

What parts fit the King Kutter 40HP gearbox?

We carry complete 40HP gearbox assemblies plus internal service parts including bearings, oil seals, gaskets, snap rings, input and output shafts, gears, caps and vent plugs. Coverage spans XB Series, Flex Hitch, standard rotary cutters and finish mowers rated at 40HP.

How do I know if my King Kutter gearbox is shear pin or slip clutch?

Shear pin gearboxes use a shear bolt style input shaft, while slip clutch models use a 6-spline input shaft. The correct input shaft, input gear, and gearbox differ between the two, so match your drive style before ordering. If you are unsure, confirm your part number with the parts team.

Will a 40HP gearbox fit my 5 foot King Kutter rotary cutter?

Yes, the 40HP gearboxes and parts cover 5 foot and 6 foot rotary cutters, along with 4 foot models, XB Series 48 inch, and finish mowers. Fitment depends on whether your machine uses shear pin or slip clutch drive, so verify the input style first.

Can I replace just the bearings and seals in my 40HP gearbox?

Yes, Broken Tractor offers individual bearings, oil seals, gaskets, and snap rings so you can rebuild a worn 40HP gearbox rather than replace the whole unit. We carry both the large and small bearings along with input and output shaft seals.

What size vent plug does the King Kutter 40HP gearbox use?

The 40HP gearbox uses a 1/2 inch 14 NPT vent plug, which also fits the 60HP and 80HP gearboxes. We stock this plug along with the 1/8 inch plug used across the same gearbox line.