TorqueFlite

TorqueFlite (also seen as Torqueflite) is the trademarked name of Chrysler Corporation's automatic transmissions, starting with the three-speed unit introduced late in the 1956 model year as a successor to Chrysler's two-speed PowerFlite. In the 1990s, the TorqueFlite name was dropped in favor of alphanumeric designations, although the latest Chrysler eight-speed automatic transmission has revived the name.

History

Torqueflites use torque converters and Simpson gearsets, two identical planetary gearsets sharing a common sun gear. Chrysler Corporation licensed this gearset from Simpson in 1955.

The first Torqueflites provided three speeds forward plus reverse. Gear ratios 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 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; 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 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 and Borg-Warner, which start out in second rather than first if the second position is selected.

With 1962 came 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 to , providing justification for 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 were selected with the vehicle moving forward above approximately . 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 to 1971.

In 1978, most Torqueflite transmissions gained a lockup 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, Dodge, DeSoto, Chrysler and Imperial. It was also used by American Motors beginning in 1972, where it was named Torque-Command, as well as by Jeep, International Harvester, Maserati Quattroporte, Monteverdibr>
and Bristol Cars, Bristolbr>
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).

Nomenclature

Torqueflite transmissions and transaxles made through 1991 were assigned arbitrary engineering designations consisting of the letter "A" followed by three digits. 1992 and later units have four-character designations in which the first through fourth characters indicate, respectively, the number of forward speeds, torque capacity, drive type or transaxle orientation, and control system:

Rear-wheel drive transmissions

A466

The original TorqueFlite was designated ''A466'', with a cast iron case, separate iron converter housing, and no parking pawl.

A727 (36RH/37RH)

The A466 was replaced in 1962 with the ''A727'' (later renamed ''36RH'' and ''37RH''), with a one-piece aluminum case to reduce weight by about . This was initially referred to in consumer-oriented publications as the "TorqueFlite 8" to differentiate it from the A904. The A727 incorporated a parking pawl, with the sole exception of the 1962 Chrysler and Dodge 880 version, which had an extension-mounted drum brake. Compared to the early cast-iron transmissions, many and various internal improvements were featured, and it used a or torque converter. The heavier-duty A727 Torqueflites became — and remain — wildly popular for drag racing, off roading, and monster truck applications because of their controllability, reliability, ease/cheapness of repair and brute strength. Note there are unique bellhousing bolt patterns for the small block "A" and big block "B" engine versions of this transmission, and for the AMC/Jeep applications.

* 1962-1978 361, 383, 400 B-Motor V8
* 1962-1978 413, 426 Wedge, 440 RB-V8
* 1966-1971 426 "Street" Hemi
* 1964-1971 426 Race Hemi (super stock, etc.)
* 1962-1966 318 "A" "Poly" V8
* 1968-1973 340 (all)
* 1969-1983 225 (Police, Taxi)
* 1971-1980 360 (4-BBl only)
* 1978-1983 318 (4-bbl Police)
* 1972-1978 AMC "Torque-Command"
* 1984-1989 318 (2-bbl Taxi special order)
* 1980-1991 Jeep (some)

Gear ratios:

A518 (46RH/46RE)

The ''A518'', later renamed ''46RH'' (hydraulic controlled governor pressure) and ''46RE'' (electronic controlled governor pressure), is an A727 derivative with overdrive, in the A500 ilk. Starting in 1990, it was used in some trucks and vans. The overdrive fourth gear ratio is 0.69:1.

Gear ratios:

Applications:
*Dodge Ram pickup and vans 150/250/350 V8 and diesel engines (DGT)
*Dodge Ramcharger SUV 1988-1993 5.2L & 5.9L V8
* Jeep Grand Cherokee 1993 5.2L, 1998 5.9L
*1995 Dodge Dakota 5.2L Magnum V8
*1996 Dodge Dakota V8
*1998–2003 Dodge Dakota ''R/T''
*1998-2003 Dodge Durango 5.9L V8 (4WD or 2WD)
*1994-1995 Dodge Ram 2500/3500 V8
*X-1995 Dodge Ram Van 2500 5.2L Magnum V8

A618 (47RH/47RE/48RE)

The ''A618'', later renamed ''47RE'' (electronically controlled governor pressure) is a heavier-duty version of A518 also known as the 46RE (which also has electronically controlled governor pressure, versus the earlier RH version, which was hydraulically controlled). It was used in trucks and vans starting in the mid-1990s. While currently used with some internal changes such as the move from aluminum to steel planetary carriers and an increase in the number of clutch plates when coupled to the 5.9 L Cummins Turbo-Diesel and the 8.0 L V-10 applications, it's still a 727 with overdrive and stronger internal parts. It has an input torque rating of . The ''48RE'' is an electronical