Porsche 7DT (PDK)

Porsche's seven-speed dual-clutch — PDK — in the 911 and Panamera.

It is a WET dual-clutch, so the low-speed judder that defines the dry units on this site is not a characteristic of it: a shudder from rest on a PDK is a fault, not the design meeting a driving habit.

Most of what owners report is behaviour. These change constantly, hold a very tall top gear, and creep differently from a torque-converter automatic — all of it designed, and best settled against another example of the same model rather than with a scan tool.

Its expensive failure is the mechatronic unit, and it presents electrically: a gear refused, a limp mode, a code naming a solenoid or a clutch position sensor. Nothing slips first, which is what separates it from clutch wear.

Fluid is a control question rather than maintenance. The oil serves the clutches and the hydraulics that move them, so worn fluid makes the gearbox change badly long before it makes anything fail — and the interval is far shorter than the word lifetime suggests.