Why Your 911 lost its Dog-Leg Five-Speed Transmission

Leonard recently unearthed a Porsche press release from 1972, talking about the transmission changes for that year: the arrival of four speeds as standard and five speeds as optional, and the replacement of the dog-leg pattern on previous 911s. This release heralds the arrival of the Porsche 915 transmission and is interesting stuff, though I wonder if its really about countering objections on why five speeds now cost extra.

To match the increased power, a new, stronger gearbox has been developed by the engineers. Due to the greater flexibility of the engines, and the associated wider power range, the standard unit could be reduced from five to four gears thanks to the better torque. For all those who do not want to forego the fifth gear, a likewise newly designed five-speed gearbox is available as optional equipment.

With this new design,  the former way of shift pattern is changed so that, in addition to the ordinary four-speed H-shift pattern, the 5th gear is placed above and to the right. The reasons are the following. When the Porsche 911 appeared for the 1st time in 7 years ago the car was equipped with a 2-litre engine. At that time the engine power was relatively low in comparison with nowadays and thus required frequent gear shifting, particularly from 5th to 4th gear. Therefore it was decided to put these gears in line, and the 1st gear (being the starting gear) to the bottom left. It was also practical because bumper-to-bumper driving in those days was still a fairly rare occurrence.

In the meantime however, traffic conditions have changed quite drastically and, when driving in the rush-hour and bumper-to-bumper traffic, constant stopping and starting is commonplace. With this in mind, the 1st gear was put in the most convenient position, as it is with most four-speed gearboxes.

On account of the greater flexibility of the engines, less frequent shifting from 4th to 5th gear and vice versa is necessary, so really this new gearbox is the perfect answer to today’s driving conditions. It is therefore obvious that, particularly under this consideration, the famous Sportomatic gearbox, which combines the fun of quick shifting and ease of an automatic is available from most models i.e. because of its growing popularity, even for the 911 S.

So, there you have it. Your 911 lost its dog-leg transmission because traffic got worse and first gear needed to move. Makes sense to me, but I wonder whether a gearbox mechanic might tell a different story to the marketing copywriter.

See the full range of WEVO 915 Transmission Upgrade Parts in the Twinspark Porsche Racing Parts Shop

1 Comment

  • Steve| March 6, 2013 at 10:03 pm

    I think it’s just marketing speil lol. For example the original 911 turbo was released with a 4 speed box because the 5 speed wasn’t deemed strong enough to cope with the torque and I recall Porsche used the same argument about engine flexibility!

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