Also known as: u661, u661e, u661f
Toyota's transverse six-speed for the larger front-drive cars — in the Lexus RX and NX.
It is the U660E's hybrid-era relative and shares its architecture; the catalogue holds the U660E separately because the applications and the fluid specification differ.
Its recurring complaint is a shudder at light throttle around 50–80 km/h, which is the torque converter's lock-up clutch rather than the transmission slipping — the same symptom, and the same first remedy, as on every lock-up automatic in this catalogue. On this one it tracks fluid condition closely enough that a service is a diagnostic step.
Where genuine faults appear it is the valve body and its solenoids, presenting electrically: a gear refused, a limp mode, a code naming a solenoid. Nothing slips first.
Toyota's WS fluid is required, and an RX at 150,000 km on its original fill is the commonest version of the shudder above.
Cars fitted with this gearbox
2 generations. Only where a source names the model and the generation together — a gearbox is documented as a product far more often than as a fitment, so this list is deliberately shorter than the truth.
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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