Mitsubishi TC-SST

Mitsubishi's twin-clutch — in the Lancer Evolution X and Ralliart.

It is a Getrag 6DCT470 and a WET dual-clutch, which is the first thing to establish: the clutches run in oil, so the low-speed judder that defines the dry units on this site is not a characteristic of it. A shudder from rest here is a fault.

It is not Suzuki's TCSS, despite the near-identical abbreviation. Three of four letters agreeing is a coincidence — different maker, different gearbox, different faults — and this catalogue's own alias search proposed the merge before a person read it.

Its dominant failure is the mechatronic unit and the clutch pack, and on a car driven as these are, the clutches are a consumable. A launch-control start is the hardest single thing anyone does to one, and the wear is measurable through the diagnostic tool as a percentage — which is what to ask for when buying.

Fluid is a specific Mitsubishi SST fluid and the interval is genuinely short — far shorter than a torque-converter automatic's, because the oil serves the clutches and the hydraulics that move them.