Also known as: tc-sst, tcsst, twin clutch sst, sst, getrag 6dct470
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.
Cars fitted with this gearbox
1 generation. 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.
Mitsubishi
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.
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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