YN32W01002P1 Swing 1st Planetary Gear 20T for Kobelco SK200-5 SK200-6 SK200LC-6 SK210LC

YN32W01002P1 Swing 1st Planetary Gear

The YN32W01002P1 planetary gear is used in the first planetary reduction stage of selected Kobelco excavator swing gearboxes. Three planet gears operate together in this stage to transfer torque while reducing swing motor speed.

This 20-tooth pinion has a relatively compact gear width and rotates around its carrier support while meshing with the surrounding reduction gears. Correct tooth contact, center bore condition and rotational clearance are all important for stable swing operation.

Because the three planetary gears work as one set, abnormal wear on a single gear should also trigger an inspection of the remaining gears and carrier support positions.

Three Planet Gears Share the First-Stage Load

The planetary arrangement divides torque across several gear contact points. Under normal conditions, each gear in the same carrier should develop a broadly similar contact pattern.

If one gear shows much heavier wear than the other two, the cause may be excessive support clearance, carrier misalignment or an uneven bearing condition rather than a defect in the gear alone.

Comparing all three gears during disassembly is therefore useful when diagnosing repeated swing gearbox failures.

Check the Center Bore and Roller Contact Area

The external teeth are only one part of a planetary gear inspection. The center bore also forms an important working surface as the gear rotates on its support inside the carrier.

Scoring, irregular bore wear or excessive clearance can allow the gear to tilt during operation. Once the gear is no longer running square to the carrier, tooth contact can become concentrated near one edge.

If abnormal bore wear is found, the roller or bearing arrangement and carrier support should be inspected before a replacement gear is installed.

Typical Wear Found on a Swing Planetary Gear

• Pitting or surface fatigue on the gear teeth

• Chipped or broken tooth edges

• Uneven contact across the tooth width

• Scoring or excessive wear inside the center bore

• Heat discoloration caused by lubrication problems

• Metal particles or fragments in the swing gearbox oil

If all three gears show similar surface damage, lubrication condition and the overall gearbox alignment should also be investigated.

Do Not Identify the Gear by Tooth Count Alone

A 20-tooth count is a useful identification point, but it is not enough by itself to confirm the correct swing planetary gear.

Gear diameter, center bore, overall width, bearing arrangement and reduction-stage position should also match the original component.

This is especially important on older excavators where the installed swing reducer may have been replaced during previous repairs.

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 front and side photos of the original planetary gear

• Confirmed tooth count

• Outside diameter and center bore diameter

• Overall gear width

These details help distinguish similar planetary gears used in different positions of the swing reduction gearbox.

Kobelco Swing Gear Parts Support from Topvelsun

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

Send us part number YN32W01002P1 or cross reference 72210029 together with your machine and original gear information, and we can help verify the application before quotation.