Editing Powerglide (section)

== History ==
The 1950 through 1952 Powerglide transmissions did not automatically shift between low and high (direct drive) which made for very sluggish take-offs and many drivers started in "Low" and shifted to "Drive" at about {{convert|30|-|40|mph|km/h|abbr=on}}. The 1953 and later units when in "Drive" started in low and automatically up shifted to high at a speed determined by the throttle opening. By the mid-1950s, more than half of all new Chevrolets were sold with Powerglide.

In 1962, GM started building Air Cooled Powerglides in [[aluminium]], primarily for use in the new model Chevy II, which required a lightweight transmission for its compact body, and discontinued the cast iron Powerglides in 1963. A heavy duty version of Aluminium Powerglide was offered for passenger cars equipped with the [[Chevrolet Big-Block engine|409 cubic inch V8 engine]], and Chevrolet light trucks using a 1.76:1 reduction planetary gear set, instead of the usual 1.82:1. With a 3.31 axle, Car and Driver magazine noted a full-throttle up shift speed of {{convert|76|mph|km/h|abbr=on}} to direct with the 409-4bbl {{convert|340|hp|kW|abbr=on}} engine in a contemporary road test. Most of the V8/Powerglide transmissions came with the 1.76 gear set. One notable exception was the ''export'' version of the transmission, which offered only the 1.82 ratio and was used by [[Holden]] in Australia behind their Australian built [[Holden motor|6-cylinder]] and V8 engines. Holden vehicles fitted with Chevrolet V8 engines used the 1.76 ratio gear-set.

The Powerglide continued to serve as Chevrolet's main automatic transmission through the 1960s, when a new three-speed automatic transmission called [[Turbo Hydra-Matic|Turbo-Hydramatic 400]] (1965 introduction) began to be phased in. They were introduced in [[Buicks]] and [[Cadillacs]] the previous year.

Usually, Powerglides were coupled with the [[Chevrolet small-block engine|small block V8s]] such as the 283 ci engine, and the third-generation [[inline-six engine|inline six-cylinder engine]] and [[Inline-four engine|inline four-cylinder engines]]. By the late 1960s, demand for two-speed automatic transmissions was dwindling as buyers were demanding three-speed units (Ford, Chrysler and [[American Motors]] had already switched entirely to three-speed automatics by this time). In 1969, the three-speed [[Turbo-Hydramatic#THM350|Turbo Hydramatic 350 (THM350)]] was introduced as a light-duty companion to the Turbo-Hydramatic 400, and made available on virtually all Chevrolet cars and trucks with six-cylinder or small and medium-sized V8 engines, as well as intermediate sized cars of other GM divisions.<ref>[http://gmautomatictransmissions.com/powerglide_transmission.php GM automatic transmissions]; Retrieved April 27, 2011.</ref>

The Powerglide lingered on as a low-cost automatic transmission option primarily for the six-cylinder [[Chevrolet Nova]] and four-cylinder [[Chevrolet Vega]] until it was phased out after the 1973 model year, replaced by the [[Turbo-Hydramatic#THM250|Turbo Hydramatic 250]]. They were also used in the DJ-5 'Dispatcher' Jeeps sold for light commercial use, and best known for their service with the [[US Postal Service]]. Its simple and robust design has led drag racing enthusiasts to work with it, giving the Powerglide an effective service life of nearly five decades past its intended obsolescence.