⚙️ Technical Information

• Part Number: 7117‑30290
• Part Name: Sun Gear No.2 (Second Stage)
• Application Area: Final drive / travel gearbox of excavators
• Function: Central gear in the planetary reduction assembly
• Used as part of the travel reduction gear set in Volvo machines.

🚜 Compatible Machines

This sun gear is commonly listed for use in Volvo excavators such as:

• EC160B / EC180B / EC160C / EC180C / EC140C
• EC210 / EC210B
• Possibly other Volvo travel gear configurations
  (Always verify exact model compatibility with your machine’s serial number)

🧩 Function in Planetary Gear System

In a planetary gearbox, the sun gear sits at the center and works with:

• Planet gears (surrounding gears)
• Ring gear (outer gear)

✔ The sun gear turns →
✔ Drives the planet gears →
✔ Transfers torque to the reduction output for the track motors.

As a second‑stage gear, it is part of the multi‑stage reduction path that increases torque and reduces speed for smooth machine travel.

⚠️ Common Failure Symptoms

When this sun gear is worn or damaged, typical issues include:

• Noise from the final drive (grinding or clicking)
• Reduced travel performance
• Erratic or rough movement
• Metal debris in the travel gearbox oil