20Y-27-22170 Planetary Carrier for Komatsu Final Drive

20Y-27-22170 Final Drive Planetary Carrier

The 20Y-27-22170 planetary carrier is an internal component of the excavator final drive reduction gearbox. It supports the planet gears and keeps them correctly positioned while torque is transferred through the planetary reduction system.

Unlike an individual gear, the carrier controls the working position of several rotating components at the same time. Its dimensional accuracy directly affects gear alignment, load distribution and the operating stability of the final drive.

For older Komatsu excavators, final drive configurations can vary by production period and machine serial number, so the original carrier and gearbox configuration should be checked before ordering.

How the Carrier Works Inside the Final Drive

During machine travel, the planet gears rotate while being supported by the carrier. The carrier maintains the spacing and alignment required for the planetary gears to mesh correctly with the other gears in the reduction system.

Because travel loads are distributed through several gear contact points, the carrier must remain rigid and accurately aligned. Wear around the gear support locations or deformation of the carrier body can cause the planetary gears to run unevenly.

Once alignment is lost, abnormal tooth contact, increased backlash, noise and accelerated wear may develop elsewhere in the final drive.

Signs the Original Carrier Should Be Replaced

When rebuilding a travel reduction gearbox, inspect the original carrier carefully for:

• Cracks or visible deformation in the carrier body

• Excessive wear around planet gear support locations

• Abnormal clearance or movement between the gears and carrier

• Damage around the center drive or spline area

• Uneven contact marks on the planetary gears

• Heavy metal particles found in the final drive oil

If one support position shows significantly more wear than the others, the mating gears, pins, bearings and surrounding gearbox components should also be inspected before reassembly.

Why Carrier Fitment Needs More Than a Machine Model

A planetary carrier can look almost identical to another version while differing in diameter, height, center spline, gear support position or internal geometry.

This is particularly important with excavators that have been in service for many years. A machine may already have received a replacement or rebuilt final drive, so the gearbox currently installed may not always match the configuration originally supplied with the excavator.

For this reason, part number, machine serial number and the dimensions of the original carrier should be used together when confirming fitment.

Recommended Checks Before Final Drive Reassembly

Replacing the carrier alone is not always enough when a travel gearbox has suffered internal damage. Before reassembly, inspect the complete planetary stage for abnormal wear and make sure all mating components move freely without excessive clearance.

The gearbox housing should be cleaned thoroughly to remove metal debris from the previous failure. Bearings, gear contact surfaces and lubrication passages should also be checked before fresh gear oil is added.

Finding the cause of the original damage helps prevent a new carrier from being exposed to the same abnormal load after installation.

Information to Send for Fitment Verification

For a more reliable match, send the following information with your inquiry:

• Excavator model and machine serial number

• Final drive or travel gearbox identification information

• Clear front and side photos of the original carrier

• Overall carrier diameter and height

• Center spline details

• Planet gear support dimensions when available

These checks are useful for distinguishing visually similar carrier assemblies used in different final drive configurations.

20Y-27-22170 Replacement Support from Topvelsun

Topvelsun supplies replacement planetary carriers, gears and other internal final drive components for excavator repair shops, equipment owners and parts distributors.

Send us part number 20Y-27-22170 together with your machine and original carrier information, and we can help check the application before quotation.