Automatic transmission revolutionized motoring
17-year research effort produced a no-clutch 1940 Olds
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Development of that most useful of automobile accouterments was a long, slow process, marked by many failures.
Contrary to popular belief, General Motors did not invent the automatic transmission. But GM definitely pioneered it and popularized it.
The principle dates back to 1904 and the Sturtevant brothers of Boston. It was a good idea whose time had not yet come. The 1934 Reo had a semiautomatic transmission, but the company was on its last legs and had neither the time nor the money to develop it.
GM had both the time and the money, and an automatic transmission was a pet project long before it saw the light of day in the 1940 Oldsmobile.
In My Years with General Motors, Alfred Sloan devotes considerable space to the corporation's work on transmissions. The quest for an automatic began in earnest in 1923 as an extension of many things that had been studied for years.
Not a new principle
"Most of the general principles that went into the making of the fully automatic transmission were known to us and were being investigated carefully at least 15 years before automatic transmissions became available in production cars," Sloan wrote.
A forerunner was syncromesh, an easier and smoother type of manual shifting. Cadillac adopted it in 1928, and all GM divisions had it by 1932.
By 1928, Sloan said, the GM Research Laboratories had decided upon an automatic-transmission technology. It was an infinitely variable steel-on-steel friction drive.
But no luck. "It turned out that this specific steel-on-steel type was not the answer," Sloan said. "I was convinced it would always cost too much, and I turned it down for our cars."
Success in 1940
So it was back to the drawing board, but the drawing board was a bit better defined. By 1934, a group of Cadillac engineers were on the right road with the Hydra-Matic, Sloan said.
Buick and Oldsmobile offered a semiautomatic in 1938 models. Buick made them, and they had a clutch pedal. The next step, Sloan said, was the clutchless Hydra-Matic that was offered as a $57 option on the 1940 Oldsmobile. Cadillac got it the next year.
After World War II, GM engineers began an intensive research program to adapt the fluid torque converter to passenger cars. It led to the Buick Dynaflow of 1948 and Chevrolet Powerglide of 1950.
Four-speeds, five-speeds, even six-speeds are popular today. But the automatic transmission clearly is the king. More than 90 percent of the cars and trucks sold in the United States today have one.
Some auto buffs consider the automatic transmission one of the two most important innovations in the history of the automobile. The other is Charles Kettering's electric self starter, which debuted on the 1912 Cadillac.
You can reach John K. Teahen Jr. at autonews@crain.com.
