3069514 Swing 2nd Sun Gear for HITACHI EX200-3 EX200-5

3069514 Swing 2nd Sun Gear

The 3069514 sun gear is used inside the swing reduction gearbox of selected Hitachi excavators. It works within the planetary reduction system to transfer rotational force through the swing gearbox before torque reaches the excavator upper structure.

Its long cylindrical gear form is different from the shorter sun gears used in other reduction stages. Correct tooth geometry, center fit and overall gear alignment are important for smooth engagement under repeated swing acceleration and braking loads.

This gear should be identified by the original swing gearbox configuration rather than machine model alone, especially on older excavators that may have received a replacement swing device during previous repairs.

Why Swing Sun Gear Wear Matters

A swing gearbox repeatedly changes load direction as the upper structure starts, stops and reverses. These operating conditions place alternating loads on the sun gear and its mating planetary gears.

If the tooth surfaces become heavily worn, the load may no longer be distributed evenly across the gear mesh. This can increase backlash, produce abnormal swing noise and accelerate wear in other parts of the planetary reduction stage.

For this reason, replacing a damaged sun gear should normally be accompanied by an inspection of the surrounding gear set.

What to Check on the Original Gear

Before rebuilding the swing gearbox, inspect the removed sun gear for:

• Pitting or flaking on the working tooth surfaces

• Chipped or cracked tooth edges

• Uneven wear concentrated on one side of the gear

• Wear or scoring around the center bore or spline area

• Heat discoloration caused by poor lubrication or excessive friction

• Metal particles in the swing gearbox oil

Uneven tooth contact may indicate a carrier, bearing or alignment problem rather than failure of the sun gear alone.

Do Not Match a Swing Gear by Appearance Alone

Several Hitachi swing reduction gears have a similar cylindrical appearance, but differences in gear height, tooth count, center bore and reduction-stage position prevent them from being automatically interchangeable.

The original gear should therefore be checked together with the swing device information and machine serial details before ordering.

This verification is particularly useful when the excavator has a long repair history or when the installed swing gearbox may not be the factory-original unit.

Information for Fitment Verification

For faster identification, send the following information with your inquiry:

• Excavator model and machine serial number

• Swing gearbox or swing device information

• Clear photos of the original sun gear

• Confirmed tooth count

• Outside diameter and center bore diameter

• Overall gear height

These details help distinguish similar sun gears used in different swing reduction configurations.

Swing Gear Parts Support from Topvelsun

Topvelsun supplies replacement sun gears, planetary gears, carriers and other internal components for excavator swing reduction gearbox repair.

Send us part number 3069514 or cross reference AT213759 together with your machine and original gear information, and we can help verify the application before quotation.