The PDK Transmission

The PDK Transmission 1
The PDK Transmission 2
The PDK Transmission 3

The PDK has a valve body like that of a conventional automatic transmission, which contains electronic shift solenoids that actuate mechanical spool valves for directing hydraulic fluid flow to the clutches and shift rods. An electronic control unit orchestrates PDK operation, and it is in constant communication with the engine control unit and the ABS/PSM control unit to optimize shift strategy and perfectly match engine revs during shifts.

The driver can control shifts via buttons or paddles on the steering wheel or with the shift lever. There is also a fully automatic mode, with the normal shift setting oriented towards smooth shifting and optimum fuel economy. When moving the vehicle from rest, the #1 (outer) clutch pack engagement is programmed to mimic the slippage of a torque converter when moving from rest, and it almost succeeds at this. Porsche considers the PDK good enough in this regard to offer it as the exclusive transmission available in the Panamera luxury/sports sedan (with the exception of exceedingly rare manual 6-cylinder models, and the Tiptronic-equipped Hybrid) and in the Macan SUV.

Sport or Sport Plus modes completely transform the shift strategy, providing firm and lightning-fast shifts at far more precise intervals than most mortals can muster. The latest generation PDK transmissions incorporate new fuel-saving modes, such as “sailing,” or decoupling the transmission from the engine to allow the engine to idle while coasting. The new 991 Turbo introduces a slightly preposterous “virtual gears” mode that slips the clutches while cruising in automatic mode to allow the engine to lug along at idle speed.

Service & Reliability

The PDK seems to be as reliable as its Tiptronic forebears thus far, with only a handful of factory technical service bulletins present. Porsche’s prescribed service intervals are 56,000 miles for the hydraulic fluid and about twice that for the gear oil, though it would be wise to change the gear oil at the same time as the hydraulic fluid.

Hydraulic fluid level check and replacement is beyond the realm of the DIYer as it requires the use of a Porsche Integrated Workshop Information System (PIWIS) or an equivalent scan tool to monitor fluid temperature and to activate the requisite “fill mode.” Clutch pack life is yet to be determined, and time will tell if Porsche’s long-term development of the PDK has paid dividends in long-term reliability.

What is certain at this time is that a two-pedal transmission in a modern Porsche is certainly not a compromise from a performance standpoint, and the PDK, in fact, outperforms most of us. Porsche customers have overwhelmingly endorsed the concept by choosing the two-pedal option 90 percent of the time.

Hopefully, the purity of a true manual transmission will still be available in Porsche cars in years to come for those of us who still yearn for that direct mechanical linkage between man and machine.

Also from Issue 226

  • 991 Carrera GTS
  • Bangkok 911
  • Market Update: 1989-1998 911s
  • A 911 racer’s R Gruppe street car.
  • Porsche’s Sporting Scout Car
  • Grant Wolfkill
  • Profile: Peter Falk
  • Enzmann 506
  • The Keeper 924
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