Editing TorqueFlite (section)

==History==
[[File:Chrysler imperial dash push button transmission=1956.jpg|thumb|Imperial dash push-button "Powerflite" transmission introduced for the 1956 models]]


Torqueflites use [[torque converter]]s and [[Simpson planetary gearset|Simpson gearset]]s, two identical [[planetary gearset]]s sharing a common [[Sun and planet gear|sun gear]]. Chrysler Corporation licensed this gear set from [[Howard Simpson]] in 1955.<ref>{{cite web|url=http://www.allpar.com/mopar/torqueflite.html|title=TorqueFlite Transmission|work= Allpar.com|access-date=May 7, 2012}}</ref>

The first Torqueflites provided three speeds forward plus reverse. [[Gear ratio]]s were 2.45:1 in first, 1.45 in second, and 1.00 in third. The transmission was controlled by a series of pushbuttons located on the vehicle's dashboard. The buttons were generally at the extreme driver's side end of the dash, i.e., the left in [[Traffic directionality|left-hand drive]] vehicles and the right in right-hand drive ones. However, this was not always the case; the 1962 [[Dodge Phoenix]], a right-hand drive export model sold in Australia and South Africa, used the U.S. 1962 [[Plymouth Valiant]] instrument cluster assembly, into the left end of which were integrated the transmission pushbuttons. Button arrangement varied by vehicle model and year; the sequence was reverse, neutral, drive, second, and first, from top to bottom with vertically arrayed buttons, from left to right with horizontally arrayed buttons, and clockwise starting at upper left with clustered buttons.

A parking lock was not provided until the advent of the aluminum-case Torqueflites in 1960 (standard-duty A-904) and 1962 (heavy-duty A-727), at which point a lever was added adjacent to the pushbuttons: Moving the lever to the "park" position placed the car into neutral and engaged a lock pawl on the transmission's output shaft. Moving the parking lever out of the "park" position unlocked the shift buttons to select a driving range. The buttons were replaced by conventional steering column- or floor-mounted shift levers in all automatic Chrysler-built vehicles for the 1965 model year. However, floor levers were available in specific sporty 1964 models.

Like a vehicle with a [[General Motors]] [[Hydramatic]], a vehicle with a Torqueflite transmission starts in first gear when the drive or second position is selected. This is in contrast to vehicles with several automatics from [[Ford Motor Company|Ford]] and [[Borg-Warner]], which start in second rather than first if the second position is selected.

For 1962, a canister-style fluid filter was installed in the cooler line. For 1964, the canister filter was eliminated, and the transmission's internal intake screen was replaced by an efficient [[Dacron]] filter. Fluid life starting in 1964 was extended from {{convert|12000|mi|km|abbr=on}} to {{convert|50000|mi|km|abbr=on}}, justifying the deletion of the drain plug from the oil pan.

For 1966, the twin-cable shift and park control mechanism (a holdover from the push-button operation) was replaced by a solid shift control linkage consisting of a series of pushrods, rotating rods, and levers. The rear pump was eliminated, which simplified and cost-reduced the transmission but rendered push-starting impossible; Chrysler engineers reasoned that improved electrical and fuel systems reduced the need to push-start vehicles, and safety concerns weighed against doing so. The gated shift quadrants also permitted the deletion of the reverse safety blocker valve, which, in TorqueFlites made through 1965, had shifted the transmission harmlessly into neutral if the reverse position was selected with the vehicle moving forward above approximately {{convert|3|mph|km/h|abbr=on}}. With the elimination of the rear pump, the oil filter was designed with a single oil port. 

In 1968, part-throttle downshift functionality was added to A-904 transmissions used with six-cylinder engines. This feature permitted the transmission to shift from third to second gear in response to moderate accelerator pressure. Previously, an automatic 3-2 downshift occurred only if the driver pushed the accelerator to the floor. This change was made to maintain acceptable in-town performance with taller final-drive ratios in the rear axle — 2.76:1 rear axle gears were being furnished in applications previously equipped with 2.93:1 or 3.23:1 gearsets. Part-throttle downshift functionality was extended to V8 A-904s in 1969, and to most A-727 transmissions in 1970 through 1971.

In 1978, most Torqueflite transmissions gained a [[torque converter|lockup torque converter]] clutch to mechanically connect the converter's impeller and turbine, eliminating slip for better highway [[Fuel economy in automobiles|fuel economy]]. This addition required the removal of the torque converter drain plug.

For 1980, a wide-ratio gearset was released for the A904, A998, and A999, with 2.74:1 in first, 1.54 in second, and 1.00 in third.

Torqueflite was an available option or standard equipment, depending on model and year, on all Chrysler products: [[Plymouth automobile|Plymouth]], [[Dodge]], [[DeSoto (automobile)|DeSoto]], Chrysler and [[Imperial automobile|Imperial]]. It was also used by  [[American Motors Corporation|American Motors]] beginning in 1972, where it was named '''Torque-Command''', as well as by [[Jeep]], [[International Harvester]], [[Maserati Quattroporte]], [[Monteverdi (automobile)]] [http://www.allpar.com/model/monterverdi.html] and [[Bristol Cars|Bristol]] [http://www.bristolcars.co.uk], as well as several brands of light and medium-duty trucks and panel vans.  When installed in Dodge trucks and vans, the transmission was marketed as '''LoadFlite'''.

In the 1990s, the transmissions were renamed. However, the original Torqueflite design remained the basis of many Chrysler-designed (and built) transmissions through 2007 (and FWD transaxles through 2000).