YN32W01007P1 Swing 1st Sun Gear for Kobelco SK200-5 SK200-6 SK200LC-6 SK210LC

YN32W01007P1 Swing 1st Sun Gear

The YN32W01007P1 sun gear is used in the first planetary reduction stage of selected Kobelco excavator swing gearboxes. It transfers rotational input into the planetary gear set as swing motor speed is reduced before torque continues through the remaining reduction stages.

Because this gear operates close to the input side of the swing reducer, it is repeatedly exposed to rapid torque changes when the upper structure starts, stops or reverses direction.

Stable gear engagement and correct alignment are therefore important for controlling backlash and maintaining smooth swing operation.

First-Stage Gears See Frequent Torque Reversals

Excavator swing operation involves repeated acceleration, braking and direction changes. Each change in direction reverses the load acting through the reduction gear set.

If the sun gear develops excessive tooth wear or clearance, impact loads can increase as torque changes direction. This may lead to abnormal swing noise and accelerated wear in the surrounding planetary components.

For this reason, a damaged first-stage sun gear should not be evaluated independently from the rest of the planetary reduction stage.

Inspect the Original Gear for Uneven Contact

During swing gearbox repair, check the original sun gear for:

• Pitting or fatigue marks on the working tooth surfaces

• Chipped or cracked tooth edges

• Uneven contact marks across the gear width

• Scoring or abnormal wear around the center bore

• Heat discoloration caused by lubrication problems

• Metal particles in the swing gearbox oil

Wear concentrated on one side of the tooth face can indicate a carrier, bearing or alignment problem elsewhere in the gearbox.

Do Not Mix First-Stage and Second-Stage Sun Gears

A single swing gearbox may contain more than one sun gear. Gears from different reduction stages can differ in height, tooth geometry, center bore and working position even when they are used in the same excavator series.

The reduction-stage position should therefore be confirmed together with the part number and original gearbox configuration.

This is especially important for older machines that may already have received a replacement or rebuilt swing reduction unit.

Information Needed for Fitment Verification

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

• Excavator model and machine serial number

• Swing reduction gearbox information

• Clear photos of both sides of the original sun gear

• Confirmed external tooth count

• Outside diameter and center bore diameter

• Overall gear height or width

These details help distinguish similar sun gears used at different positions in the swing reduction gearbox.

Kobelco Swing Gear Parts Support from Topvelsun

Topvelsun supplies replacement sun gears and other internal swing reduction components for excavator gearbox rebuilding, repair and parts distribution.

Send us part number YN32W01007P1 or cross reference 72210022 together with your machine and original gear information, and we can help verify the application before quotation.