Why do some Prius models experience a whining o r humming noise from the transmission?

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Why do some Prius models experience a whining o r humming noise from the transmission?

A whining o r humming noise is often linked to worn-out transmission bearings, inverter issues, o r normal regenerative braking sounds. Discussing when the noise is normal versus when it indicates a problem can help owners avoid unnecessary repairs.

Lubaba asked on 13 Feb 2025 12:56:03 pm

1 Answer

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Car Mechanic Expert - on 13 Feb 2025 13:04:32 pm

A whining o r humming noise could be caused by:

Worn transmission bearings: Bearings inside the eCVT can wear out over time, causing noise and performance issues.
Inverter issues: The inverter manages power between the engine, battery, and motor. Failure of this unit can cause strange noises and power loss.
Regenerative braking: Some sounds are normal and come from the regenerative braking system, especially at low speeds.

Tip:
If the noise is constant and changes with speed, it’s best to consult a mechanic to rule out more serious issues.