Diagnosis: Likely the electronic speed control (trigger) or the brushless motor (if equipped) operating normally, or a sign of a lack of lubrication in the gearbox.
Action checklist:
- Identify the noise: A smooth electronic whine at low speed is often normal for variable speed triggers. A grinding or grating whine is not.
- Run the drill with no load (no bit). Does the noise change with speed? A consistent pitch that varies with trigger pull is likely electronic.
- Check the chuck is tightened securely. A loose bit or chuck can cause vibration.
If the noise is new, loud, or grinding:
- Stop using the drill.
- Remove the battery.
- Inspect the chuck and gears for visible damage or debris.
- Manually rotate the chuck. It should turn smoothly with slight resistance. Roughness indicates internal issues.
Heads up: Normal operational noise is not a defect. Persistent grinding, squealing under load, or loss of power with noise indicates a mechanical fault. Covered under the 3-year warranty for EU-purchased tools with CE mark.