(March 9, 2017) Chevrolet pitched its new 3-speed Turboglide transmission in the V8-equipped 1957 Chevrolet in this 90-second TV ad. It was a $50 option over the standard Powerglide 2-speed automatic transmission and was available from 1957-1961.
It consisted of a concurrently geared (as opposed to sequentially geared) planetary gearbox. It was designed to help showcase the engineering features of the '57 Chevy and was often ordered with the Rochester RamJet fuel injected system on the 283 V8.
The transmission used a five-element torque converter and offered the smoothest operation of any automatic in the industry, as no "shift" occurred between the ranges and hence there was no disruption in the flow of power.
Chevrolet engineers Ed Cole, Robert Benzinger, and Frank Winchell, hit upon an idea for a transmission that would offer a smoother, less abrupt feel during acceleration. They designed a torque convertor with three separate turbines, one for each of the transmission’s speeds. The first engaged the low gear as soon as the vehicle took off from a dead stop. As speed increased, oil passed to the second turbine while the first continued to spin on its built-in sprag gear. Finally, as the car reached cruising speed, the final turbine engaged the high gear.
This approach had the effect of starting all speeds at once; that is, the transmission was running all three speeds simultaneously. The car started out in “1-2-3” mode, went down to “1-2,” and ended up in “1.” In this way, the Turboglide was similar to the continuously variable transmissions (CVTs) that are used on some of today’s cars. And therein lies one of the major problems with public reception: Americans love the “vroom” sound and feel that occurs when an automatic transmission shifts from one speed to the next.
The Turboglide eliminated that sensation, leading to the same types of complaints heard about CVTs today.
For that reason as well as others including build quality problems, the Turboglide disappeared with the 1962 model year.
Sources: Wikapedia, ETE Product Support blog