Porsche's PDK Gearbox Has One Fascinating History

Humble Beginnings

Today, most consider the Porsche dual-clutch - or PDK - transmission to be one of the very best in the business, a sturdy, reliable, quick-shifting gearbox that's a perfect match for its sports cars. However, many may not realize that the development of the PDK began a whopping 40 years ago when Rainer Wust - a transmission test engineer - began developing what would eventually become one of the more famous such units in the world.

Photos: Porsche

Passion Project

"The idea was to combine the best of two worlds - the advantages in the degree of efficiency of a manual transmission and the potential for performance of full automation, which still had many weaknesses at the time," Wust said. "It was a huge challenge for a small department such as ours. Maybe it was naivety that helped us, but certainly, our pragmatism in dealing with the challenges did - as well as our passion for this subject."

Photos: Porsche

Solid Start

Wust started out by pulling some old developmental prototypes designed by Imre Szodfridt from storage, which provided a solid baseline for the PDK's development. "Szodfridt was a very clever man, so this preliminary work helped us," Wust said. "We got the Szodfridt transmission from storage and worked with pneumatic valves, which we converted to work hydraulically. It was complicated pioneering work from the ground up, but the result already had pre-series status."

Photos: Porsche

Testing Process

A special 944 Turbo was used as a test bed for the new PDK back in the 1980s, but Wust and his team were eager to test the new transmission out in a motorsports application. Before long, they managed to do just that with the 956. "We were able to change gears and drive significantly faster without interrupting the engine’s drive," said legendary driver Hans-Joachim Stuck. "Being able to keep my hands on the steering wheel when changing gears at full throttle felt great right from the start."

Photos: Porsche

Big Problem

"Jacky Ickx quickly learned to brake with his left foot when cornering and accelerate with his right to keep the turbo going," Wust said. "This made him significantly faster coming out of a corner." But there was still a problem. - the transmission would "kick" forward every time there was a gear change. "These jerks put great stress on the transmission - and the entire driveshaft," Wust said. "On a few occasions, this excess torque sent everything flying around us, and I sat at home in the evenings and nearly gave up on the whole thing."

Photos: Porsche

Enduring History

Thankfully, Wust didn't give up on the PDK. The rest, as they say, is history. After reducing the inertia of the transmission, Porsche went on to use it to win at Monza in 1986, bring home the 1986 World Sports-Prototype Championship, and even score first place in the Semperit-Rallye at the end of 1985. The PDK bowed in the 911 in 2008 and hasn't looked back since.

"PDK is definitely a highlight of my 38 years at Porsche," Wust said. "There were many lovely projects, and this was one of the loveliest. A lot of what you work on ends up in the bin. But this is here to stay, I can feel it. This makes me proud. When I see a car with PDK on the road today, I know: a piece of me is inside that. And this is a wonderful development."

Photos: Porsche

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