Читать книгу Chrysler TorqueFlite A-904 and A-727 Transmissions - Tom Hand - Страница 9

CHAPTER 1

HISTORY, IDENTIFICATION AND EVOLUTION OF THE A-904 AND A-727 TORQUEFLITE

The TorqueFlite transmission, introduced in the mid-1950s, was a simple, yet advanced, engineering masterpiece. Compared to its contemporaries it was exceptionally well designed, functional, robust, lightweight, and adaptable to different torque levels. In 1956, the relative of the A-904 and A-727, the A-466, was an option in Chrysler Imperials. The A-466 had a cast-iron body, aluminum converter housing, and aluminum tail shaft housing. The forward-gear ratios were 2.45:1 (low), 1.45:1 (second), and 1.00:1 (direct); reverse was 2.21:1. The A-466 Torque-Flite transmission was offered in 1957 Imperials and other Chryslers. Prominent ads and reviews heralded the A-466 as “the best automatic in the world.” This TorqueFlite, like later versions, had a three-element torque converter coupled to an automatically shifted 3-speed Simpson gear set operated by two bands, two multi-disc clutch assemblies, and a one-way clutch. The aluminum case A-904 TorqueFlite was introduced in 1960 and the A-727 in 1962. With its torque converter, the A-727 weighed about 160 pounds.

The A-727 has been used in thousands of cars, trucks, vans, and SUVs since its 1962 introduction.

Around 1965, the bolt-on driveshaft yoke changed to a slip yoke and the push-button shifter changed to a traditional column or console shift. In addition, because Chrysler products had become so reliable, the necessity for a push-starting system disappeared, eliminating the need for the output shaft-rotated rear oil pump.

After these major design changes occurred, the TorqueFlite stayed fairly consistent; it enjoyed a long run and the A-904 lived until 2003. Anyone who inspects the first and last one can see that they are essentially the same transmission. A 43-year run for any car part is unheard of, but because of the great design by Bert Cartwright, Erv Miller, and Teno Iavelli, the TorqueFlite experienced it.

A tour of the Kokomo plant provided memories and these drink holders.

The TorqueFlite used in some trucks was called a LoadFlite and those in AMC vehicles were called Torque Commands; for consistency in this book, TorqueFlites will be referred to as A-904s and A-727s.

The Manufacturing Facility

The first cast-iron TorqueFlites were built at the Kokomo Transmission plant in Kokomo, Indiana. After a run of cast-iron units, production of the first aluminum A-904s began around 1959 and in 1962, the aluminum A-727 went into full production. Around 1977, the Kokomo plant began the lock-up converter-equipped TorqueFlites and the front-wheel-drive TorqueFlites went into production.

Identification

Most A-904s and A-727s have a number stamped on the pan rail above the oil pan on the driver’s side. This transmission assembly number usually had a “PK” followed by seven digits. The seven-digit number (used until around 1990) was sometimes followed by an alphabetical plant code, a warranty date code, and a four-digit daily production number based on a 10,000-day calendar. Reported data indicates the 10,000-Day Date Correlation numbers started in 1962. For example, January 1, 1972, is a 3812 and January 1, 1982, is 7462. The first 10,000-day date calendar concluded in the late 1980s.

Many think this 1962 Dart (with a Polara grille) is out of the ordinary; with a big-block, 4-barrel, and new-for-1962 A-727, it was.

This historically significant A-727 transmission case (PK1942275) was cast in 1961.

The last three part number digits were stamped on some converters. This is a 1977 high-stall, non-lock-up converter.

Late TorqueFlites had eight-digit part numbers. This lock-up (PK52118017) had a high-stall converter and was used in a 3.9-liter-powered 1994–1996 truck.

Along with a three-digit number, some converters had a four-digit date code. This 6093 possibly came from a late 1977 production run.

The Pushbutton and Cable-Shift Mechanism

The early TorqueFlites were shifted by an ingenious push-button mechanism. Each button moved a lever/plate that controlled a cable connected to the valve body. The reverse plate had a tab to trigger and activate a reverse light switch. When used, a Park lever reset the other buttons and pulled the park pawl into the parking gear to lock the output shaft. Around 1964–1965, the push-button shifter changed to a traditional column or console shift. A reason given is a mid-1960s Federal Government mandate that all drivers were to have available a standardized way of selecting gears. Because the pushbutton arrangement was so unique among automakers, Chrysler “stood out” and had to change. ■

A push-button shift module controlled early TorqueFlites. This 1962 Dart has a manual valve body and its buttons get pushed a lot!

The module controls the valve body/park mechanism through the gearshift control cable and a parking lock cable.

These small cables transfer driver signals to the valve body.

The mechanism consists of plates, levers, and springs that advance or retract the gearshift control cable. A separately activated Park lever “cancels” all gears and moves the parking lock cable.

A tab on the reverse plate actuates the reverse switch. When the tab pushes forward, it moves the “V”-shaped linkage to hit the switch and turn on the reverse lights.

This end of the cable fits in the case. The large ring (control cable adjusting wheel) rotates on the threaded ferrule to pull/push the gearshift control cable.

In the park cable housing, an adapter hooks on the park lever to pull it on or off.

TorqueFlites with small-block engines have 7.75 inches between these top two holes.

A-727s for big-blocks and HEMIs have about 6.25 inches between the holes.

Beginning in 1969, a pad on the bellhousing in front of the dipstick tube was stamped with an abbreviated version of the Vehicle Identification Number (VIN): eight numbers match the last eight on the VIN.

Some torque converters are identified by a stamped four-digit date code and the last three digits of its part number; these are located on the crowned surface of the converter close to the weld seam.

Early A-904s were manufactured for 6-cylinders and small V-8 (small-block) engines. A-727s were produced for 6-cylinders, small-blocks, and big-blocks including the Hemi. To determine which engine they fit, measure the space between the top two holes on the bellhousing. Small-block TorqueFlites have about 7.75 inches between the bolts, big-blocks have about 6.25 inches, and 6-cylinder TorqueFlites have the starter high on the bellhousing.

Production Numbers and Transmission Identification

Appendix A lists the available production numbers and usage information for A-904s and A-727s.

Evolution of the TorqueFlite A-904 and A-727

All of the 3-speed TorqueFlites are very similar and incremental changes occurred yearly to make them stronger, smoother, and more efficient. It would take a very large chapter to detail all of the changes made, so a very abbreviated list of key, year-to-year engineering and production changes is provided.

1960

Production of the A-904 for Slant-6 engines in lightweight cars occurs.

1961

The A-904 was modified for the torque of the 225-ci Slant-6.

1962

The A-727s for V-8 applications were manufactured and strong versions were used with the powerful 413-ci engines. Trucks received their first A-727s.

1963

A heavy-duty A-904 went into Police cars and Taxis and a stronger A-727 found its home in the 300J Chrysler. A-727 Truck usage expanded to include the Forward Control A-100.

1964

Minor updates were made to the A-904 and the 413-ci, the 426-ci Wedge, and the 426 Hemi received robust A-727s. Six-cylinder versions went into trucks.

1965

The A-904 was strengthened and a high-performance version with a higher-shifting governor went into 273 4-barrel A-bodies. Highperformance big blocks and Street Hemis got a beefed-up A-727. The bolt-on yoke changed to a sliding yoke.

1966

The rear pump was eliminated from A-904s and A-727s and both got rod-operated shift linkage, eliminating use of shift cables. A more positive Park lock mechanism was introduced.

1967

A part-throttle kickdown circuit was used in 6-cylinder A-904s. The rear servo piston changed and a “stiff spring-integral cushion” went into A-904s and A-727s. The A-727 got an enlarged input shaft; and 440s and Hemis got high-strength shafts identified with a yellow paint stripe and a groove. Four-pinion planetaries were used in high-performance A-727s.

1968

The A-904 was strengthened for the new 318 by incorporating a larger input shaft and other changes. The output shaft front spline diameter increased and a one-hole filter was adopted for the A-904 and A-727.

1969

The single terminal neutral start switch picked up two more terminals to control reverse lights. Valve bodies were modified for the new switch and they received a “reverse pressure” relief ball. A VIN pad was added to the case and the bolt-on oil fill tube was changed to a push-in design.

1970

A-904s and A-727s for new E-bodies received a shift control linkage boss on the left side. The 1–2 shift valve governor plug was changed to speed up the manual 1–2 shift. The A-727 for 440 6-barrel cars received the 426 Hemi TorqueFlite internals. An A-727 was released for the 413 truck engine.

1971

A-904s were modified for economical 1.6- and 1.8-liter Simcas. Part throttle downshift circuits were introduced for A-904s and A-727s. The A-727 had a running change/introduction of the wide bushing front clutch retainer, a reaction shaft support with new sealing rings, and the front clutch retainer shorter lip seals.

1972

The A-904 received short lip seals in the front clutch retainer. The A-727 rear clutch spacer ring changed from steel to nylon. A heavy-duty extension for truck A-727 was added. AMC and International Harvester adopted TorqueFlites. A-727 extensions on Imperials were fitted with dampener weights.

1973

Valve bodies received revised throttle and line-pressure adjusting brackets, enabling “computerized” pressure adjustments during assembly. The oil filter was enlarged by 50 percent. Part-throttle kickdown circuits went into trucks. The flexible A-727 (flex) kickdown band arrived.

1974

Neutral-to-Drive and Neutral-to-Reverse shift quality improvements were made by adding valve body restrictions and check balls. The A-727 rear clutch assembly received a stronger Belleville spring washer. A governor filter was added and A-904s got their first stamped-steel planetaries. The A-999 heavy-duty “mini-Hemi” version of the A-904 was built for 360-ci engines. The A-998 for 318s was released with the A-999-type front clutch retainer components.

1975

Some trucks featured rear timing holes in the bellhousings. Valve bodies were changed to reduced part throttle downshift sensitivity.

1976

A new valve body filter prevented regulator valve sticking. The A-727 output shaft front planetary spline angle changed from 45 degrees to 37.5 degrees. The A-904 thrust washer between input and output shaft changed to steel-backed bronze; all A-904s had a Teflon seal ring on the input shaft. The A-727s received tin-nickel-plated front clutch seal rings, the rear servo piston lip seal changed to Viton, and front clutch inner and outer seals changed from lathe cut to molded. Use of redesigned converters began.

1977

An A-904 was released for Colts and Arrows and a 1978 transmission design “built out” 1977 compact trucks.

1978

Lock-up converter-equipped A-904s and A-727s received new pumps, reaction shaft supports, input shafts, and valve bodies. The A-727 was equipped with a tabbed thrust washer between input and output shaft, the neutral start switch was shortened, and magnets were placed in oil pans. A-998s and A-999s received controlled-load kickdown servos.

1979

The A-904 received a controlled-load kickdown servo and a thin, polished-steel thrust plate for the third thrust washer. The A-727 case was modified to accept lock-up valve bodies and they were changed to improve converter lock-up. The A-998s and A-999s had check balls added in the transfer plate and other changes to eliminate “reverse squawk.”

1980

Wide-ratio gear sets for A-904s and flexible kickdown bands for standard and wide front clutch retainers were introduced. An AMC four-wheel-drive A-904 version was used and truck extension housings were strengthened. The governor weight body diameter was increased by .070 inch to allow common tooling. A-998 and A-999 valve bodies had 1–2 and Neutral-to-Drive quality improvements. Six cylinder applications had revised lock-up springs.

1981

The A-904 and A-727 cases were changed for shift quality improvements.

1982

The AMC and MMC A-904s featured wide-ratio gear sets. Minor case changes occurred and a Viton rear servo piston seal was introduced for fleet A-904s.

1983

The A-999 had the lock-up speed increased in vehicles with 2.2:1 rear axles. Slant-6, non-lock-up A-727s were released for California. All A-904s had Viton rear servo piston seals.

1984

A non-lock-up A-999 was released for high-altitude (car) use. The A-727 truck transmissions for 318 and 360 with high-stall converters received four-pinion front planetaries, four-disc front clutch retainers, and a special Borg Warner kickdown bands. A new A-904 case went into production for postal trucks.

1985

A-904s for AMC diesels were released. Vans and wagons had standard, long A-727 extension housings instead of the heavy-duty truck version.

1986

Part throttle converter unlock was used across the board for all 318 (A-999) and 225 (A-904) lock-up transmissions. A threaded hole was added for the lock-up solenoid connector on the A-904 case along with other changes to the valve body due to the solenoid. A-999s and A-904s received heavy-duty extensions for long wheelbase trucks.

1987

Some truck A-727 transmissions were released with a stronger rear bearing. The Dakota’s A-998 received new exhaust support mounting locations; a new four-wheel-drive transmission was produced. Reverse bands for A-904s and A-727s were changed to a (non-asbestos) Kevlar material. Mitsubishi 1.6-liter vehicles received an A-904.

1988

The overrunning clutch changed from a 10-roller to a 12-roller design in the A-904 family.

1989

The A-727 reaction shaft was modified to increase oil flow to the number-3 thrust washer, and the reaction shaft support was heat treated and polished. The A-727 non-lock-up transmissions were modified for Cummins diesels.

1990–1993

The Park sprag was widened and the number-3 thrust washer was made more durable. Material was removed from all input shafts and A-727 output shafts. The A-727 reverse band anchor strut and link assembly were modified to accommodate reinforced band lugs. The A-999 sun gear shell thickness was increased by .035 inch and the thrust plate’s thickness was decreased. A-998s and A-999s were used in 3.9- and 5.2-liter trucks. A-998 and A-999 front clutch retainers added a rear bushing. The A-904 family oil pumps switched from tabs to flats on inner gear rotors. Some 1991 and later A-727s had 14-roller-overrunning clutches.

1994–1996

The A-904 was renamed to the 30RH; the A-998 was 31RH; A-999 was 32RH and A-727s were known as a 36RH in 5.2-liter trucks. Rear planetaries received five pinions on some A-727s and steel front planetaries with five pinions went into some HD trucks.

1997–1999

The 36RH continued use in the AB-van. The speedometer gear was replaced with a vehicle speed sensor.

2000–2003

In 2001, the 32RH replaced the last 36RH for AB-vans until production of the 3-speed TorqueFlite ended (2003).