Fault Phenomenon: Amco Veba truck crane a periodic “clunking” sound occurs during swing.

Troubleshooting Process:
– Checked swing ring gear: tooth surface pitting.
– Checked gearbox gears: primary gear had broken teeth.
– Checked lubricating grease: dried out and failed.
– Replaced swing gearbox assembly.

Root Cause: Internal gearbox gear had broken teeth.

Required Parts: Swing gearbox assembly.