TorqueFlite


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 replaced with alphanumeric designations, although the latest Chrysler eight-speed automatic transmission has revived the name.

History

Torqueflite transmissions use torque converters and Simpson gearsets, two identical planetary gearsets sharing a standard sun gear. Chrysler Corporation licensed this gear set from Howard Simpson in 1955.
The first Torqueflites offered three forward speeds plus reverse. Gear ratios were 2.45:1 in first, 1.45 in second, 1.00 in third, and 2.20 in reverse.
The transmission was controlled by a series of push buttons on the vehicle's dashboard. The buttons were generally located at the extreme driver's side end of the dash, i.e., on the left in left-hand drive vehicles and on the right in right-hand drive ones. Exceptions included the 1962 Dodge Phoenix, a right-hand drive export model sold in Australia and South Africa, which used the standard 1962 U.S. Plymouth Valiant model year instrument cluster assembly, with the transmission push-buttons integrated on the left side.
The button arrangement varied by vehicle model and year; the sequence was reverse, neutral, drive, second, and first, arranged top to bottom with vertically aligned buttons, from left to right with horizontally aligned buttons, and clockwise, starting at the upper left with clustered buttons. The neutral button had to be engaged before starting the engine. In some applications, the button also activated the starter.
A parking lock was not provided until the advent of the aluminum-case Torqueflites in 1960 and 1962, at which point a lever was added adjacent to the push-buttons: 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 from 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. Floor shift levers were available in some 1964 models. The levers always used the P-R-N-D-2-1 sequence.
Like the operation of General Motors' Hydramatic transmissions, Torqueflites start in first gear when the drive or second position is selected. This contrasts with vehicles equipped with automatic transmissions from Ford and Borg-Warner, which begin 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 an efficient Dacron filter replaced the transmission's internal intake screen. Fluid life starting in 1964 was extended from to, justifying 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 reduced the cost of the transmission but rendered push-starting impossible. Chrysler engineers reasoned that improved electrical and fuel systems reduced the need for push-starting vehicles, and safety concerns outweighed the benefits of 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 driver selected the reverse position while the vehicle was moving forward at speeds 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 pressed 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 and 1971.
Starting in 1978, most Torqueflite transmissions were equipped with a lockup torque converter clutch, which mechanically connected the converter's impeller and turbine, thereby eliminating slip and improving highway fuel economy. This addition required the removal of the torque converter drain plug.
For 1980, a wide-ratio gearset was introduced for the A904, A998, and A999, featuring a 2.74:1 ratio in first gear, 1.54 in second gear, and 1.00 in third gear.
Since 1962, a version of the Torqueflite was an available option or standard equipment, depending on model and year, on rear-wheel-drive Chrysler products: Plymouth, Dodge, DeSoto, Chrysler, and Imperial. When installed in light-duty Dodge trucks and vans, the transmission was marketed as LoadFlite.
The Torqueflite replaced Borg-Warner automatics in American Motors Corporation cars beginning with the 1972 model year, and AMC marketed them as Torque-Command. After 1979, AMC discontinued offering the Hydramatic in Jeeps to join the rest of AMC's models.
Other automakers using the Torqueflite included International Harvester, Maserati Quattroporte, Monteverdi, and Bristol, as well as several brands of light and medium-duty trucks and panel vans.
In the 1990s, the transmissions were renamed. However, the original Torqueflite design remained the basis of many Chrysler-designed and built transmissions through 2007.

Nomenclature

Torqueflite transmissions and transaxles made through 1991 were assigned arbitrary engineering designations consisting of the letter "A" followed by three digits. The 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, 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 being that for 1962 the Chrysler, Imperial, and Dodge 880 A727s had an extension-mounted drum parking brake instead of a parking pawl. 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. There are unique bellhousing bolt patterns for the small block "A" and big block "B" engine versions of this transmission and for American Motors and 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
  • 1962–1966 318 "A" "Poly" V8
  • 1968–1973 340
  • 1969–1983 225
  • 1971–1980 360
  • 1978–1983 318
  • 1972–1978 AMC "Torque-Command"
  • 1984–1989 318
  • 1980–1991 Jeep
Gear ratios:

A518 (46RH/46RE)

The A518, later renamed 46RH and 46RE, 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:
The A618, later renamed 47RE is a heavier-duty version of A518, also known as the 46RE. 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 is a 727 with overdrive and more robust internal parts. It has an input torque rating of. The 48RE is an electronically governed, ECU-controlled, four-speed heavy-duty overdrive automatic transmission, that is stronger than its predecessor, the 47-series. The 48RE was introduced in 2004 to 3rd gen ram pickups with the 5.9 cummins, or the v10, some 03 and early 04 trucks still were equipped with 47RE units, and then came a 48re which still used a TV cable, and then from 04.5 to 07 the 48re was fitted with a TTVA motor which eliminated the need for a mechanical TV cable. 48re units had the highest volume pump out of any of its predecessors, using a 10 lobe design with tighter clearances versus the 47REs 11 lobe design for additional holding ability. More volume was on tap to be circulated through the larger cooling circuit. with the higher than ever low end cummins torque, the direct drum was bigger to allow 5.085" frictions and 5.084" steels, the forward drum is in fact made bigger to make room for the 5th direct friction/steel, the 48s forward clutch frictions switched from a 64 tooth to a 93 tooth inner spline count, 6 pinion, steel planets were introduced with more robust thrust washers backing them, the overdrive housing was slightly enlarged in the parking mechanism areas to allow the bigger parking rod and pawl mechanism. Most importantly the valvebody introduced the ability to have 2nd gear tcc lockup in manual second. A handful of other enhancements, part throttle 3rd gear tcc lockup was a big quality of life enhancement.
The base design from the original Torqueflite remains essentially unchanged. The addition of a two-speed output shaft that is bolted to the back of the three-speed transmission has only two ratios: direct and overdrive. While lubrication to the overdrive unit was a challenge early on, this was overcome with factory improvements or aftermarket valve body kits. The overdrive planetary has six-pinion gears, which is often used as an aftermarket replacement for the stock four-pinion planetary used with the lighter duty transmissions.
Gear ratios:
Applications:
  • Dodge Ram pickups 2500/3500 ISB Diesel and iron V-10
  • Dodge Ram SRT-10
  • 1994–1995 Dodge Ram 2500/3500 Diesel/V10
  • 1996–2002 Dodge Ram 2500/3500 Diesel/V10
  • 1998–2000 Aston Martin Virage V8 5.3L
  • 2003–2004 Dodge Ram 2500/3500 ISB Diesel
  • 2003–2004 Dodge Ram 2500/3500 HO ISB Diesel
  • 2004–2007 Dodge Ram 2500/3500 600/610 Diesel
  • 2004–2006 Dodge Ram SRT-10