Prius transaxle: noise, shudder and the motor-generators

There is no conventional transmission in a Prius: two motor-generators and a planetary gear set do the job inside the transaxle. A shudder on take-off, a whine at speed or a clunk when stopping can come from here, but the shops rule out mounts, damper and fluid first.

What owners notice

A shudder pulling away, a whine that rises with speed, a clunk when stopping or starting, or warning lights from the hybrid drive.

What the shops check first

The simpler causes: engine and transaxle mounts, the damper between engine and transaxle, fluid condition and level, and wheel bearings that can sound like drivetrain noise. Then the hybrid system's motor data and codes.

What the repair usually involves

Mounts, a damper or a fluid service fix many of these complaints. When a motor-generator, bearing or the transaxle itself has failed, the shops replace the affected assembly and explain the cost against the value of the car first.

What the shops' records show

The count at the top of this report is every repair order matching this problem across the EV Partners shops, recounted from their Shop-Ware records whenever they sync. Below it, each shop that has done this work shows its own share, the model years it saw and what it did, with a link to its own write-up where one exists.