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Surprisingly, many of the mechanisms
and technologies that make the
modern automatic transmission
operate were already in use during
the rather lengthy genesis that
manual transmissions went through.
Transmission
bands and planetary gears were
used in the manual transmission
for the Ford
Model T and Model K (1906).
Fluid coupling was used by General
Motors as early as 1937.
Even
more surprising, these technologies
were first developed in the early
1900s in Germany for use in marine
applications.
Semi-automatic
transmissions appeared in a major
automotive brand in 1937. General
Motors dubbed these "the
Automatic Safety Transmission"(AST).
With planetary gears and a conventional
friction clutch, these transmissions
allowed easier shifting and required
less driving skill. Cadillac and
Oldsmobile issued models with
AST through 1939. Buick used the
AST only in 1938. The AST never
inspired the driving public and
was not supported by large sales
numbers.
The
1948 Oldsmobile was the first
model to use a true automatic
transmission. The Hyrdo-Matic,
developed by GM engineer, Earl
Thompson, was advertised as "The
greatest advance since the self-starter."
The Hydro-Matic went through continual
upgrading and refinements through
1955. But, the basic design and
theory used were consistent throughout
its remarkably long life span.
Over the years the Hydro-Matic
was used in many military applications
including the M5
Stuart tank and the M24 Chaffee
light tank. Other auto manufacturers
purchased and used the Hydro-Matic.
These included:
Even into the 1990s, the Hydro-Matic
was used, in modified versions,
for drag racing and hotrod applications.
One company in particular made
the "B&M
Hydro" a mainstay of
performance enthusiasts for decades,
and in cooperation with Andy
Granatelli, made the Hydro-Matic
the only automatic transmission
to ever be used in Indy Car racing.
General
Motors replaced the Hydro-Matic
in 1956 with the Jetaway.
The "Jet" was not a
roaring success and quickly gave
way to the Turbo Hydromatic.
Chrysler's
Fluid Drive was introduced in
1939, but this was really a manual
transmission that used a fluid
coupling to make shifting easier.
Chrysler first produced a semi-automatic
transmission in 1942 and was late
in developing their own true automatic
transmission, introducing the
two-speed PowerFlite
in 1954.
BorgWarner
engineered the first automatic
transmission used by Ford, introduced
in 1950.
Americans
lead the way in deploying automatics.
Mercedes
introduced their first automatic
in 1962. Rolls Royce's 1955 intro
was with GM's Hydro-Matic. Daimler
(then owned by Jaguar) first used
a BorgWarner 4-speed in 1962.
Through
the 1980s changes and advances
occurred quickly. Special features
seemed to be the primary focus
of transmission designers.
Options
included:
Manual-or-automatic
shifting - allowed
drivers
to take control of the shifting
when
they
wished
Push-button
shifting - a Chrysler
Torqueflite
innovation
that used a two-cable mechanism
Edsel's
Teletouch shifting - buttons in
the
middle
of the steering wheel that operated
an electric
shift motor
Economy-performance settings -
the
driver could reset with the push
of a button
Over-drive
in 3, 4, and 4-plus-overdrive
configurations
Hill-hold
- prevented the vehicle from
rolling
backwards at idle on an upgrade
Ignition
lock coupling - anti-theft feature
Editor's
note:
The following is hardly a history
chapter. Rather, it is a quick
overview of transmission technology
since the 1980s. Please check
back at a later date to view additional
history entries. Last update:
November 2, 2006
In
the late 1980s, as onboard computers
became prevalent, came the introduction
of electronic controls for automatic
transmissions. Solenoids and sensors
integrate with multiple onboard
computers to control shifting
and gear ratio in any imaginable
scenario.
Honda's
Hondamatic, originally a two-speed,
was reborn in 1979 as the H3 three-speed.
This transmission is unique in
that it is an automatic that does
not use planetary gears. Gears
slide on parallel shafts. The
Hondamatic is similar neither
to other automatic transmissions
nor to manual transmissions.
Five-speed,
six-speed, seven, and even eight-speed
transmissions are currently being
used in automobiles. Such technologies
are being tested and deployed
in an effort to improve economy
and efficiency.
CVTs provide
continuous torque at engine peek-performance
speeds
In
a return-to-roots sort of trend,
transmission research and development
is currently leaning toward Automated
Manual Transmission technologies.
Please
check back at a later date to
view additional history entries.
Last update: November 2, 2006.
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