An Enduring Legacy

While many changes have been made to the automatic transmission over the years, the original concept implemented by GM proved hardy in various niche markets. Even as late as the 1990s modified versions of the original Hydra-Matic design were being used in the building of various types of racing vehicles including drag racers and hotrods.

But by reason of the availability of better technologies and — some would argue — out of sheer necessity, the automatic transmission was given many updates, redesigns and overhauls. One of the more beneficial updates has come in the form of the standardization of many of the parts that make up the automatic transmission.

Challenges and Changes

In its early days, so many changes were made to the design of the automatic transmission that the parts became increasingly less interchangeable. This made for difficult and often costly repairs, especially on older model vehicles. Some parts achieved a degree of obsolescence so far gone that it became virtually impossible to find replacement parts and, subsequently, made repair of the transmission equally impossible when those parts failed.

Changes to the automatic transmission were gradual but steady over the following decades bringing with them many more basic enhancements. Among them were the standardization of the PRNDL configuration (which provided much needed additional control for the driver and safer overall operation of the vehicle) and the ability to select and hold a single gear to compensate for steep hills and severe weather conditions.

Development Hits Top Gear

The 1980s saw a time of rapid advancement in technology that allowed for various features to be implemented. Many complex features and enhancements to the automatic transmission were born of advancing technologies during that time period. Some of these features included:

Hill Hold — a feature that kept the car from rolling backward while idling on an incline.

Manual or Automatic Shifting — this gave the option back to the driver to shift gears at manually controlled intervals, but also allowed the freedom to not have to hold the clutch or shift with a gear shifting lever.

Economy Performance Settings — gave drivers the freedom to select shifting options for increased fuel efficiency

Overdrive — available in automobiles with 4- or 5-speed transmissions, also for fuel efficiency, especially at low speeds (city driving) and high speeds (motorway speeds).

And the list goes on. The 1980s also saw the advent of electronically controlled transmissions as more cars began being manufactured with onboard computers. This led to numerous advancements over the last three decades which have resulted in innovative technologies like the Continuously Variable Transmission (CVT) which can calculate an endless number of gear ratios for purposes ranging from increased fuel efficiency to compliance with various terrains, road conditions and driving styles.

More recent innovations have also led to the Dual-Clutch Transmission, a largely retro-designed automatic transmission system used in larger Diesel-fuelled vehicles. The DCT has had its share of design problems, mostly stemming from flaws within the hydraulic system. Many workarounds have been attempted including the integration of a manual valve body with the automatic DCT transmission with little favourable result.Porsch e911 Automatic Gearbox