Fiat Dualogic

Fiat's automated manual — in the 500, Panda, Punto, Bravo, Doblò, Fiorino, Uno, Palio and the Lancia Ypsilon and Musa.

It is an ordinary manual gearbox with a robot bolted to it, and understanding that answers most of what people find strange about it. There is no torque converter, so the car does not creep the way an automatic does; there is a real clutch, which wears like a manual's and is a wear item rather than a fault; and the pause on the change is the robot doing what a driver's left foot would.

The failure that dominates this transmission is neither the clutch nor the gearbox: it is the hydraulic actuator. The unit that works the clutch and selector carries a pump, an accumulator and a pressure sensor, and when it can no longer hold pressure the car refuses to select a gear and shows a warning, often after sitting overnight, often intermittently at first. It is very commonly diagnosed as a failed clutch and replaced as one, and the symptom returns immediately.

A clutch change on a Dualogic is not finished when the clutch is in. The system must be re-taught its bite point with a diagnostic tool; skip that and the car judders from rest and hesitates on every change — exactly the complaint the new clutch was meant to cure.

And it is not the C635 DDCT. Fiat's later dual-clutch is a different transmission with different faults; a search that does not distinguish them returns advice for one about the other.