Hyundai A6GF1 / A6MF1

Hyundai's own transverse six-speed automatic — in the Accent, Veloster and Kia Rio, and across most of the two companies' front-drive range.

Hyundai designed and built it in-house, at a point when a manufacturer at this level would ordinarily have bought an Aisin or a Jatco. So advice written about "a six-speed automatic" in a Korean car very often describes the wrong gearbox, and the transmission's own name is the thing to search.

Its recurring complaints are behavioural and respond to adaptation. A firm or delayed 1–2 change when cold, a hesitation from rest, and a reluctance to kick down are all far more often a relearn and a software update than a part — and both companies have issued transmission control updates for exactly these.

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, which distinguishes it from clutch wear.

The fluid is Hyundai's SP-IV and it is not lifetime, whatever the handbook implies — worn fluid is what wears the solenoids it is supposed to lubricate.