TorqueFlite

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TorqueFlite
Automotive industryChrysler Corporation
Production1956–
PredecessorPowerFlite
Car classification3- or 4-speed Automatic transmission

TorqueFlite (also spelled Torqueflite) was the Registered trademark name of Chrysler Corporation's three-speed Automatic transmission, which was introduced late in the 1956 Model year. TorqueFlite was introduced on the heels of the company's two-speed PowerFlite automatic, which made its debut in 1954. In the 1990s the TorqueFlite name was dropped and the transmissions were referred to by a model number referring to their torque rating and gear set, although some models remained completely unchanged.

Contents

History


The first Torqueflites provided three speeds forward plus reverse. Gear ratio 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 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; 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 Torqueflite in 1960 (standard-duty A-904) 1962 (heavy-duty A-727), at which point a lever was added adjacent to the pushbuttons: Throwing the lever to the "Park" position placed the car into Neutral and engaged a lock pawl on the transmission's output shaft. Throwing the park lever out of "Park" position unlocked the shift buttons so that a driving range could be selected. The buttons were replaced by conventional steering column- or floor-mounted shift levers in all automatic Chrysler-built vehicles for the 1965 model year, though floor levers were available in certain sporty 1964 models.

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

1962 brought the addition of a canister-style fluid filter 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 12,000 to 50,000 miles (80,000 km), providing justification for the deletion of the drain plug from the oil pan.

For 1966, the twin-cable shift and park control mechanism 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 were selected with the vehicle moving forward above approximately 3 mph (5 km/h).

In 1968, part-throttle downshift functionality was added to A-904 transmissions used with 6-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 to 1971.

In 1978, most Torqueflite transmissions gained a Torque converter clutch to mechanically connect the converter's impeller and turbine, eliminating slip for better highway 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, Dodge, DeSoto, Chrysler and Imperial automobile) and on various American Motors Corporation (AMC) beginning in 1972 (known as TorqueCommand), Jeep, International Harvester, Maserati Quattroporte, Monteverdi [1] and Bristol [2] brand vehicles as well. When installed in Dodge trucks and vans, the transmission was marketed as LoadFlite.

In the 1990s the transmissions were renamed, however the Torqueflite remains the basis of all current Chrysler designed transmissions. Jeep used several other manufacturers' transmissions until 1997, and Mercedes-Benz uses its own design identified by the number "722". Also several of the pickup lines now use transmissions from various sources. 

Technology


Torqueflites use a Torque converter and the so-called "Howard Simpson gearset," two identical Planetary gearset sharing a common sun gear. Chrysler Corporation licensed this gearset from Simpson in 1955.


Rear-wheel drive transmissions


A488

The original TorqueFlite was designated A488, with a Cast iron case and no parking pawl.

A727

The A488 was replaced in 1962 with the A727 (later 36RH and 37RH), with an Aluminum case to reduce weight by about 60 pounds (27 kg). The A727 incorporated a parking pawl and various internal improvements, and used a 10.75 inches (273 mm) or 11.75 inches (298 mm) torque converter. The heavier-duty A727 Torqueflites became — and remain — popular for Drag racing and Monster truck applications because of their controllability and strength.

A518

The A518, later 46RH (hydraulic) and 46RE (electronic), is an A727 derivative with Overdrive (mechanics). Starting in the early 1990s, it was used in trucks and vans. The overdrive fourth gear ratio is 0.69:1.

Gear ratios:

1 2 3 4 R
2.45 1.45 1.00 0.69 2.35

Applications:

A618

The A618, later 47RH (hydraulic) and 47RE (electronic), is a heavier-duty version of A518. It was used in trucks and vans starting in the mid-1990s. While currently used with some internal changes when coupled to the 5.9 Liter Cummins Turbo-Diesel and the 8.0 V-10 applications, it's still a 727 with overdrive and stronger internal parts. It has an input torque rating of 450 lb·ft (610 N·m).

Gear ratios:

1 2 3 4 R
2.45 1.45 1.00 0.69 2.21

Applications:

48RE

The 48RE is an electronically-governed 4-speed heavy-duty overdrive automatic transmission, stronger than its predecessor the 47 series.

Gear ratios:

1 2 3 4 R
2.45 1.45 1.00 0.69 2.21

Applications:

A904

For standard-duty applications in smaller and lighter vehicles with 6-cylinder or small V8 engines, the compact A904 (later 30RH) was introduced in 1960. This transmission used a 10.75 inches (273 mm) torque converter. There was also a smaller version of this transmission used in the Dodge Colt/Plymouth Champ cars made by Mitsubishi in Japan. This smaller transmission used a 10 inches (250 mm) torque converter.

A998/A999

The A998/A999 (later 31RH, 32RH, respectively) was a heavier-duty, wide-ratio version of the small-frame A904 transmission for use with medium-power V8 engines and the 3.9 L V6 engine.

The 904 was equipped with three or four direct friction plates. The 998 had four, and the 999 came with either four or five.

These automatics had lower first and second gear ratios to allow the lower-powered engines to provide better acceleration without sacrificing highway fuel economy.

A500

The A500, later 40RH/42RH (hydraulic) and 40RE/42RE (electronic), was an A904 derivative used in trucks and vans. Introduced in the 1989 model year on a limited basis, it was the first light-duty Chrysler four-speed automatic and was placed behind the 3.9 L and 5.2 L engines for light duty purposes. A tailshaft overdrive unit was bolted to the rear of the case to provide a total of four forward speeds, and was replaced by the 42RLE in 2004.

Gear ratios:

1 2 3 4 R
2.74 1.54 1.00 0.69 2.21

Applications:

  • 1989-2001 Dodge Ram pickup 150/1500 V6/V8(2WD)
  • 1989-2003 Dodge Ram Van B150/B250 V6/V8
  • 1989-2003 Dodge Dakota V6
  • 1993-2004 Jeep Grand Cherokee I6

Front-wheel drive Transaxle

The A404, A413, A470, and A670 are front-wheel drive Transaxle derivatives of the A904 Torqueflite.

In the late 1970s, Chrysler designed the A404 TorqueFlite 3-speed Automatic transmission Transaxle for its Front wheel drive Dodge Omni and Plymouth Horizon subcompact cars. This transaxle would be upgraded in the 1980s into the A413 and A670 units, which were progressively heavier-duty, for Chrysler's Chrysler K cars and their derivatives, including the minivans. The 4-speed Ultradrive electronic 4-speed automatic transaxle would eventually replace it, but the 3-speed lasted for more than a decade after the 1989 debut of the 4-speed unit.

A404

The light-duty A404 was used with the smallest Straight-4 engines from Chrysler, commonly the 1.7 L Volkswagen unit.

A413 or 31TH

The A404 was strengthened to become the A413 (later 31TH) in 1981. This was used with Chrysler's 2.2 L and 2.5 L K-car engines. It was available both with and without a Torque converter. This transmission was also used in the Dodge Neon from 1995 to 2001. The A413 is broadly similar in concept to Ford's Ford ATX transmission 3-speed unit.

A415

The A415 was developed for the 1.6 L Simca 1100 engine, but was not released for series production.

A470

The A470 was an additionally-strengthened version of the transaxle, used with the 2.6 L Mitsubishi Astron engine in the K-cars from 1981 to 1985 and Chrysler minivans from 1984 through 1987.

A670

The highest-specification 3-speed transaxle was the A670. It was used with the 3.0 L Mitsubishi 6G7x engine V6 engine in Chrysler's cars and minivans from 1987 through 2000.

Gear ratios:

1 2 3 R Final
2.69 1.55 1.00 2.10 3.02

See also

References

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