Who Built The First Automatic Transmission, And What Was The First Car To Use It?
Today, let's look at who's to blame for all the cars that insist on shifting for themselves. Arguably, the earliest blame-havers could be Louis-Rene Panhard and Emile Levassor, who were about to show off their new automatic transmission in 1894 when the thing just broke, forcing them to turn the demonstration into a Ted Talk with a chalkboard.
Then, in 1904, when concepts such as radio, television, and TikTok were still yet to be realized, two brothers with the last name of Sturtevant were plugging away at the Sturtevant Mill Company in Boston, patenting all sorts of industrial machines, including an automatic transmission and the awesome-sounding "Double Carburetor for Explosive Engines." Their primitive automatic only had two speeds, sort of like a GM Powerglide, but its operation was much different than later automatic transmissions and their weird interiors laden with forbidden mysteries.
The Sturtevant automatic used a pair of clutches attached to spring-loaded weights. These weights would slide outward with centrifugal force, causing them to engage at different engine rpm. At idle, neither clutch transmitted engine power to the forward gears, and it was essentially in neutral. The brothers would eventually design a single set of weights that both clutches would share, add a third gear, and even develop a system that likely placed multiple transmissions in a line for either four or six forward gears.
If you lived in 1904 and were already tired of shifting for yourself, you could buy a Sturtevant Automatic Automobile that rode on a 108-inch wheelbase and used a 314.2-cubic-inch H-4 engine with about 30 hp. If you needed a proper way to shake your fillings loose, you could have waited until 1906, when Sturtevant released a ludicrously huge 475.2-cubic-inch inline-4 with a brawny 50 hp.
Changing gears
Not to besmirch the forward-thinking Sturtevants, but there are two main reasons most discussions of modern automatic transmissions focus more on Canadian steam engineer Alfred Horner Munro's pneumatic four-speed auto, designed in 1921 and patented in 1923. First, apparently the Sturtevant transmissions could suffer an issue where the weights flew apart, which can be considered a bit of a problem. Secondlly, Sturtevant automobiles started at $3,500 at the cheapest, which is more than $119,000 in 2025 dollars, and some models cost nearly twice that. While Sturtevant Inc. still exists, the company abandoned automobiles by the end of 1907.
Where Munro's design flourished while Sturtevant's withered is in how gear changes were made. No, this isn't the beginning of an argument about whether all automatics should have a column shifter or a floor shifter; we're talking about the actual function of the transmission itself. Sturtevant automatics shifted based on engine rpm, not accelerator position, so no matter the power band of the engine or the load on the vehicle, the shifts would occur at a set engine speed unless the centrifugal weights were manually adjusted. Munro's design formed the basis for the GM Hydra-Matic, which determines when to shift based on throttle, not just rpm.
The modern automatic arrives
Munro's design wasn't exactly viable as-is, either, though, since air pressure wasn't a practical or viable way of transmitting power. To solve this, a pair of engineers from Brazil named Fernando Lehly Lemos and José Braz Araripe used hydraulic fluid instead. GM bought Lemos and Araripe's prototype in 1932 and debuted the now-famous fluid-coupling driven Hydra-Matic in 1940.
Before the Hydra-Matic hit the market, a pair of semi-automatic transmissions helped ease the public into accepting a car that did way too much work for them. In 1933, the REO Motor Company released the Self-Shifter, which still needed the driver to operate the clutch when getting the car moving, though it would handle shifts from there. Next came the Oldsmobile Automatic Safety Transmission, which was basically a Hydra-Matic with a clutch rather than the fluid coupling, and it operated the same way as the REO Self-Shifter.
Finally, in October 1939, the Hydra-Matic appeared for the 1940 model year in Oldsmobiles and 1941 in Cadillacs, saving drivers from the onerous task of determining their own gear selections. The Hydra-Matic was even adopted for use in M5 Stuart and M24 Chafee tanks in World War II, meaning there's an alternate timeline where the automatic transmission was never invented and M1 Abrams tanks instead rock H-pattern Tremec T56s. Instead, we live in the timeline where Aston Martin, the automaker, is building houses. Sometimes the world isn't fair.
