Buick Motor Division
General Motors Sales Corporation
Release Date: 15 October 1937
Buick Self-Shifting Transmission
An automatic transmission, that shifts itself once the car is in motion and provides marked improvement in case of car handling, economy, and performance; is one of the outstanding engineering developments of the year to be found on the 1938 Buick Series 40 Special cars. The new transmission, which is optional at extra cost, is the outgrowth of many years of development and experimentation by General Motors Research and Buick Engineers. It is regarded as the first fundamentally automatic gear shift to be entered in volume production in the automotive industry.
The new “Self-Shifting” transmission is produced in a newly constructed factory within the Buick plants representing an investment of $5,000,000 for plant and equipment alone. One of the show places of the industry, the plant is devoted exclusively to the manufacture of automatic transmissions and is equipped with the newest and finest precision machines, tools and instruments know to the automobile trade.
The transmission will shift itself once the car is in motion, and automatically provides a selectivity of gear ratios to meet all road conditions. Moreover, the self-shifting transmission is sensitive not only to the speed of the car and road conditions, but also to the will of the driver. Controls are located on the steering post just under the steering wheel at the right. This eliminates the gear shift lever in the center of the front seat compartment, making the compartment roomier and more comfortable, particularly for three passengers.
Among advantages of the automatic transmission as developed by Buick, is the fourth speed direct drive which is claimed to have important advantages over the customary overdrive transmission; and exceptional acceleration and get-away in third and lower gear ratios when driving in traffic, passing other cars on the highway or in making usually steep grades.
Claimed for the new transmission are automatic shifting with greater flexibility than in conventional gear shifts, 80% less clutch operation, about 18% reduction in engine revolutions per minute, greater gasoline mileage, unusual improvement in oil economy, better acceleration, longer engine life and greater convenience and safety.
The transmission has four forward speeds and one reverse, with forward speeds divided into two ranges -- a low range and a high range. The low range permits the use of first and second speeds only; the high range the use of first, third, and fourth speeds (direct drive). Normally, the car is started in the conventional manner in the low range by releasing the clutch, moving the control level to the low range position, then engaging the clutch and pressing the accelerator pedal. There is nothing new to learn.
The car will start in low gear and automatically shift to second. As the car gains momentum, the control lever is moved to the high range position without touching the clutch pedal, and the transmission will shift itself, first to third gear, and then into direct drive.
The operation is simple and eliminates virtually all of the manual and pedal effort involved in conventional gear shifting. It likewise is more efficient than manual operation in that the gears shift themselves according to engine speed and load with the result that shifts are made at precisely the right moment, which does not always hold with manual operation.
Among the many desirable features of the new self-shifting transmission is its ability to provide powerful acceleration at cruising speeds on the highway when that acceleration is needed. If travelling at less than 60 mph and more than ordinary acceleration is needed, it is necessary only to depress the accelerator pedal, when the transmission will shift automatically from fourth into third gear. This operation brings into action a great rush of power that cannot be equaled by anything on the road. The car automatically returns to fourth speed either when the car exceeds 60 mph or the accelerator pedal is eased up calling for less acceleration.
Proving ground tests showed that the car with the self-shifting transmission in direct drive required an engine speed of 3000 revolutions per minute at 70 mph, while the standard transmission car required an engine speed of 3700 revolutions per minute, or 23.4% greater engine speed. This great difference in engine speed accounts for smoother operation, longer engine life, increased fuel economy, and lower oil consumption of which the cars equipped with self-shifting transmission are capable.
It is held by Buick engineers that the new automatic transmission will appeal in many ways to the motorist who is looking for exceptional performance. It requires no new driving habits, but is does provide a new order of performance and safety on the road, coupled with increased overall economy.