Fluid clutches — fluid couplings and torque converters — have many advantages for automotive transmissions, but with those benefits comes a cost: fuel-wasting hydraulic slippage even at cruising speed. Since the 1940s, automakers have come up with a variety of strategies for reducing or eliminating that slip, including series parallel “split torque” transmissions and different types of converter lockup clutches. In this installment of Ate Up With Motor, we take a look at how GM, Ford, Chrysler, Packard, and Studebaker have approached this slippery problem from 1949 through the late eighties. Continue Reading Giving Slip the Slip: Lockup Torque Converters and Split Torque Automatic Transmissions
I discovered earlier that in the recent update of the Hydra-Matic article, I had made an embarrassing error in the description of the 1937–1939 Automatic Safety Transmission. The error is now corrected, but if you want a more detailed explanation, see below. Continue Reading Hydra-Matic Erratum
I have spent a lot of time over the past few weeks undertaking an extensive update of the 2010 article on the original GM Hydra-Matic transmission. The goal was to clear up various errors and points of confusion as well as trying to do a better job of explaining the operating principles of both Hydra-Matic and its precursor, the Automatic Safety Transmission.
This endeavor, which has reminded me why I’m neither a mechanic nor an engineer, was actually a good deal more work than the original draft. However, since people continue to read and refer to this article, I felt it was appropriate to try to sort out its inaccuracies and confusing points.
The Hydra-Matic, GM’s first fully automatic transmission, was a great success, inspiring a host of rivals — including some within General Motors itself. In this installment of Ate Up With Motor, we look at the origins of Dynaflow and Powerglide, the ambitious but ill-fated Turboglide and Flight Pitch Dynaflow (a.k.a. Triple Turbine), the later Controlled Coupling Hydra-Matic and Roto Hydra-Matic, and more.
AUTHOR’S NOTE: This article, originally written in 2010, has been extensively revised and expanded for 2016.
GM’s original Hydra-Matic transmission was one of the most important innovations in the history of the automobile. It wasn’t the first automatic transmission, but it was the first one that really worked and its resounding commercial success paved the way for every subsequent auto-shifter. This week, we take a look at the origins of the Hydra-Matic and its originator, Earl Thompson, who also developed the first Synchro-Mesh gearbox back in the 1920s.
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