Turbo-Hydramatic
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Turbo-Hydramatic | |
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Overview | |
Manufacturer | |
Successor | 4L60-E/4L65-E 4L80-E/4L85-E |
Turbo-Hydramatic or Turbo Hydra-Matic is the registered tradename for a family of
The Turbo-Hydramatic or Turbo Hydra-Matic (THM) series was developed to replace both the original Hydra-Matic models and the Buick Dynaflow. In its original incarnation as the Turbo-Hydramatic 400, it was first used in the 1964 model year in Cadillacs. The Buick version, which followed shortly thereafter, was known as the Super-Turbine 400. By 1973, THM units had replaced all of GM's other automatic transmissions including Chevrolet's Powerglide, Buick's Super Turbine 300, and Oldsmobile's Jetaway. Starting in the early 1980s, the Turbo-Hydramatic was gradually supplanted by four-speed automatics, some of which continue to use the "Hydramatic" trade name.
Although the Turbo Hydra-Matic name alludes to the original Hydra-Matic developed by General Motors' Cadillac division in the late 1930s, the two transmissions were not mechanically related.
Super Turbine 400 / TH400 / THM400 / THM375 / 3L80 / 3L80HD
This section possibly contains original research. (February 2024) |
The THM400 can be visually identified by an oil pan number four shown at General Motors Transmission Pans. First introduced for the 1964 model year under the name "Turbo Hydra-Matic" in Cadillacs and "Super Turbine" in Buicks. The following year, application expanded to Oldsmobile and Pontiac and to some full-sized Chevrolets.
Many of the BOC (Buick, Oldsmobile, Cadillac) THM400s produced between 1964 and 1967 were equipped with a variable-pitch
THM400 units had a 32 spline output shaft. A variant known as a THM375 is a THM400 built to mate to the smaller driveshaft yokes typically used for THM350 applications. They used a Chevrolet bolt-pattern case with a longer 27 spline output shaft inside a matching tailhousing cast with a "375-THM" or "TH375" identifier. Internally, the clutch packs originally had fewer friction plates. THM375s were found in some 1971-76 Buick Lesabres and Oldsmobile Delta 88s with the 5.7 liter V-8. Somewhere in the Mid-'80s Chevrolet C10 Pickups could also come equipped with a THM375. Some "Heavy Duty" THM350s were also designated THM375-B.
Another variant is the 3L80HD, often referred to as a Turbo 475. The 3L80HD has a straight-cut planetary gear set. There is no externally visible way to determine whether the transmission contains the straight-cut planetary gear set. The THM425 front wheel drive transmission shares almost all its internal parts with the THM400. Checker Motors Corporation used the Chevrolet version of the THM400 for its "A" series taxi and Marathon models until the end of production in 1982.
By 1980, the relatively heavy THM400 was being phased out of usage in passenger cars in response to demand for improved fuel economy. The THM 400 was utilized in the C- and K-series (full-size) Chevrolet/GMC pickups and G-series (full-size) vans until 1990 when GM switched over to the 4L80E. Today, the
Through the end of the '70s substantially more CBOP (Cadillac/Buick/Oldsmobile/Pontiac) bellhousing THM400s were produced than any other THM400. Chevrolet bellhousing THM400s, while not rare, can be hard to find and are, as a result, usually more expensive to buy (they were commonly found in 3/4 ton (8500 GVW and above) Chevrolet/GMC trucks and vans (includes the P-series box vans and 1983-86 CUCVs) when RPO M40 was checked off the option list - especially when coupled to a
Other auto manufacturers have used the THM400 and its 4L80E successor, including
THM400 transmissions are very popular in automotive competition due to their great strength. Much of this strength comes from the use of a cast iron center support to suspend the transmission's concentric shafts that join the clutch assemblies to the gear train. The center support, which is splined to the interior of the transmission's case, also provides a robust reaction point for first gear (the gear train's reaction carrier is restrained from counter-rotating the engine in first gear by a
The THM400 was the first three-speed, Simpson-geared automatic to use
For 1987, GM changed the nomenclature of their Turbo Hydramatic transmissions — the THM400 was renamed '3L80' (three forward speeds, longitudinal positioning, and an arbitrary strength rating of 80, the second highest such rating assigned). The 3L80HD was introduced in 1987 as the HD unit used in passenger trucks. In 1991, a four-speed overdrive version, the 4L80-E, replaced the THM400 in Chevrolet/GMC pickups, vans, SUVs, and commercial vehicles. The 4L80E (and its successor 4L85E) was the first Hydramatic to incorporate electronic controls — almost all of the THM400/3L80/3L80HD's components are interchangeable.
Transmission fluid cooler line connections are found on the right-hand side of the THM400. The lower connection is the cooler feed, and the upper connection is the return.[1] The case is tapped for either 1/4" National Pipe Straight NPS fittings,or 1/2"UNF fittings with a washer seal. 5/16" or 3/8" rigid coolant lines are generally connected via appropriate double-flared adapters.
Four-wheel drive truck applications used 3 various shorter output shafts that coupled with a female transfer case input shaft. Early transfer cases mated directly to the THM400 with a cast-iron adapter, usually a vertical oval shape. Later models used a circular style iron adapter which is generally considered the stronger of the two. The shortest was used with the NP203 transfer case.
Gear | Ratio |
---|---|
1 | 2.48:1 |
2 | 1.48:1 |
3 | 1.00:1 |
R | 2.07:1 |
THM350
This section possibly contains original research. (February 2024) |
The Turbo Hydra-matic 350 was first used in 1969 model cars. It was developed jointly by Buick and Chevrolet to replace the two-speed Super Turbine 300 and aluminum-case Powerglide transmissions. So, although it carries the Turbo Hydra-matic name, the Hydra-matic Division of General Motors had little, if anything, to do with its design. The 350 and its 250, 250C, 350C and 375B derivatives have been manufactured by Buick in its Flint, Michigan plant, and by Chevrolet in Toledo and Parma, Ohio and Windsor, Ontario.
The THM350 was also regarded[by whom?] as a 'three speed Powerglide'[according to whom?] and during its development, was generally called this.[according to whom?] Although it uses the same torque converter as the THM400 (without variable pitch stator) it has a familial resemblance[vague] to the 1962-73 aluminum Powerglide from Chevrolet and was largely derived from the Chevrolet design. An important difference in the THM350 compared to the THM400 is that there is no fixed center support midway through the geartrain; this difference in layout would have permitted the THM350 to be adapted to the Corvair where the drive and driven ends are the same, but this feature was not exploited. Air-cooled versions (with a baffle on the torque converter and air intakes cast into the bellhousing) of the THM350 appeared mid-1972 in the Chevrolet Vega and Nova 6.
One THM350 weak point was excessive end-play between the pump and center support and resulting wobble of the direct clutch drum due to both the end play and use of a relatively narrow bushing in the drum. This weak point can be addressed by using an extra thrust washer between the planetary gear and direct clutch to remove the end play and using a wider aftermarket bushing in the direct clutch drum.[according to whom?] Another weak point is the relatively thin center support and the lightweight matching splines in the case. This weakness can be addressed by using an inexpensive aftermarket case saver kit.[according to whom?]
Four-wheel drive truck applications for the THM350 used an iron adapter that mated it to the transfer case directly, similar to the THM400. The THM350 adapter was cast iron and used a sliding sleeve to couple the transmission output shaft to the transfer case input shaft with a steel coupler sleeve that was splined to accept both shafts and couple them together. An internal snap ring inside the coupler sleeve controlled the sleeve's position on the shafts, with circular seals in the adapter sealing the transmission from the transfer case.
For the 1981 model year, a lock-up torque converter was introduced which coincided with the new EMC control of most GM cars; this version is the THM350-C, which was phased out in 1984 in GM passenger cars for the 700R4.
THM250
This section possibly contains original research. (February 2024) |
The THM250 is a derivative of the THM350 and was introduced for 1974 in Chevrolets as a Powerglide replacement. Internally, the THM250 is a THM350 without the intermediate clutch pack and with a band adjuster similar to the Powerglide. The THM250 was usually coupled to smaller displacement engines - the largest a third generation Chevrolet inline six found in the Nova and Camaro (1974 and 75 model year only). During the 1976 model year the THM250 was phased out of production, replaced with the lighter duty THM200. It was later reintroduced in 1979 as the THM250-C in the wake of the failure-prone THM200/200C - the later 250C was further lightened with the use of a sun gear shell used with the THM350 but with 3 holes to reduce rotating mass and the low/reverse piston with 8 cutouts.
Gear | Ratio |
---|---|
1 | 2.52:1 |
2 | 1.52:1 |
3 | 1.00:1 |
R | 2.07:1 |
THM200
This section possibly contains original research. (February 2024) |
After the 1973
It was GM's first transmission which used a throttle valve cable (similar in design to the Chrysler Torqueflite part throttle kickdown linkage) controlling the shift points and part throttle kickdown. This setup was later incorporated into the THM700R4.
Because the THM-200 shared external dimensions and output shaft size and spline count with the THM-350, the THM-350 was often used to replace the weaker, less reliable THM-200 and THM-250C. The only thing which had to be added was a vacuum line to the vacuum modulator on the THM-350.
Starting with the 1979 model year, vehicles which had the THM-200/200C as standard equipment were optioned with the THM250-C, which is a THM-350 without the intermediate clutch pack along with an adjustable band similar to the Chevrolet Powerglide. Also in the 1980 model year, the THM-200 received a lockup torque converter, and some internal components (primarily the low/reverse clutch drum and planetary gears) were later shared with the Turbo-Hydramatic 200-4R. The low/reverse sprag (roller clutch) assembly was also shared with the 1988-04 Chrysler Torqueflite 904 (also 30, 31, 32RH) and its derivatives e.g. the A500 and 42RE. THM200/200Cs were produced until 1987.
Gear | Ratio |
---|---|
1 | 2.74:1 |
2 | 1.57:1 |
3 | 1.00:1 |
R | 2.07:1 |
THM200-4R
This section possibly contains original research. (February 2024) |
The 200-4R was introduced for the 1981 model year. Some components[
However, this transmission was also prone to failure (especially in D-body Cadillacs) and received improvements during its production run. The first improvement came in 1984 with a change of a servo piston from using split Teflon sealing rings to a servo using lip seals. A real problem area was the stamped-steel drive shell, which would strip out, losing reverse. With the 1985 production run, GM started installing a hardened drive shell, but continued to supply the original style until parts inventories were exhausted. Another major problem area was the pump assembly. The pump halves were made of cast aluminum and the pumps themselves were made of made up of steel segments like a power steering pump. There was a steel hub and variable ratio outer ring. Because the pump segments traveled in an eccentric circle, guide rings were necessary on top and bottom of the center hub. These rings would break and cause the pump to stop pumping, as well as damaging the aluminum housings. Aftermarket hardened rings solved this problem.
Unlike the 700R4, most 200-4Rs have a multicase bellhousing for use with Chevrolet, Buick/Olds/Pontiac (BOP), and Cadillac engines. However, 200-4Rs share mounting locations with the TH-400. Since the external dimensions are longer than the TH-350 but the drive shaft yoke spline count/diameter was the same, the 200-4Rs can be swapped in place of TH-350s, with the shortening of the drive shaft, in older vehicles to provide an overdrive gear. Early models[
The THM200-4R can be found in the following vehicles:
- 1981–90 B-bodies
- 1981–84 C-bodies
- 1983–88 G-bodies
- 1985–90 D-bodies
- 1989 Pontiac Firebird Trans Am Indy Pace car (with the turbocharged LD5 Buick V6and a turbocharger)
The THM200-4R was phased out after 1990; its final usage was in the
Gear | Ratio |
---|---|
1 | 2.74:1 |
2 | 1.57:1 |
3 | 1.00:1 |
4 | 0.67:1 |
R | 2.07:1 |
THM700R4 / 4L60 / 4L60E / 4L65E / 4L70E
This section needs additional citations for verification. (February 2024) |
This section possibly contains original research. (February 2024) |
The four-speed Turbo Hydra-Matic 700R4 was introduced for the 1982 model year for use in Chevrolet/GMC vehicles.
In 1990, the Turbo Hydra-Matic 700R4 was renamed the 4L60. Under the new designation, the "4" stands for the number of forward gears, the "L" for longitudinal applications (rear-wheel-drive), and the "60" is the strength rating (less than the 4L80). "60" is the relative torque value. For example, 80 is stronger than 60, which is stronger than 40, etc. A 4L80-E can handle more torque than a 4L60-E. The "E" denotes electronically controlled shifting. The 4L60 however is hydraulically shifted based on governor pressure and throttle valve (TV) cable position. 1992 was the last year of widespread usage of the 700R4 (4L60). The 1993 Camaro, Corvette and Typhoon were equipped with the last production 700R4. The last design change of the 700R4 was an added checkball to the valve body. In 1992 electronic controls were added, and it became the 4L60-E. The 4L60E is not easily swapped with the 4L60, as the 4L60E depends on a powertrain control module (PCM) to shift.[2] The 4L60E went into service in trucks, vans, and SUVs in 1993 and in all RWD passenger cars (Corvette, F and B/D bodies) in 1994. In 2001, an updated version — the 4L65-E, was introduced. Five-pinion planetaries, along with a strength-improved output shaft, were improved to withstand the 300+ lb·ft (400+ N·m) of torque of the 6.0 Vortec engine. The 4L70E transmission is the same as a 4L65E with a speed sensor located in the pump.
Technical description
The Turbo Hydra-Matic 700R4 can be identified by a rectangular-shaped oil pan with 16 bolt holes.[3]
The tailshaft housing is held onto the main case by four bolts (the bolt spacing is similar to the THM350), and uses a square-cut o-ring seal, and not a gasket. The typical width of this transmission where it bolts to the engine is 20 in (51 cm) overall. From the engine/trans mating surface to the cross member mount bolt is 22.5 in (57 cm), and engine/trans surface to output shaft housing mating surface is 23.375 in (59.37 cm) overall, with the tail shaft housing typically measuring 7.625 in (193.7 mm). External dimensions are similar to a THM350 with a 9-inch tailhousing found in Chevrolet/GMC long wheelbase truck/vans and 1971-76 B-bodies (Bel Air, Impala, Caprice).
Transmission fluid cooler lines on the 700R4 the bottom fitting on the right side of the transmission is the "out" line to the cooler and the top fitting is for the return line from the cooler. These fittings are .25 in (6.4 mm) pipe thread, and can include an adapter from the factory for threaded steel lines in a SAE size. 4L60Es manufactured after 1995 use snap-in connections instead of threaded. The original version of the transmission had a 27-spline input shaft (shared with the THM200C and 2004R) which was a common failure point. In 1984, the 700R4 designed for use behind Chevrolet small block V8s received a 30-spline input shaft similar to those found on TH400 transmissions and which also used a different torque converter than its 2.8 V6 and 2.2 L4 engines. Between 1984 and 1987, internal components, from the ring gear to the oil pump housing, were updated, ending with the auxiliary valve body for 700s manufactured after October 1986.
In 1995, the 4L60E received a
Gear | Ratio |
---|---|
1 | 3.059:1 |
2 | 1.625:1 |
3 | 1.00:1 |
4 | 0.696:1 |
R | 2.29:1 |
Applications
- 1982–2000 Chevrolet C/K / GMC C/K / Sierra
- 1982–1992 GMC Jimmy
- 1982–2012 Chevrolet & GMC full-size vans (including GMC Savana)
- 1982–2005 Chevrolet Corvette
- 1982–1985 Chevrolet Impala
- 1982-1996 Chevrolet Caprice
- 1983–1985 Oldsmobile 350 Diesel equipped models
- 1983–2002 Chevrolet Camaro/Pontiac Firebird
- 1984–2010 Chevrolet Suburban/GMC Suburban/GMC Yukon XL
- 1985–2005 GMC Safari
- 1988–2012 Holden Commodore
- 1989–2003 GMC Sonoma
- 1989–1994 Chevrolet S-10 Blazer
- 1989–1994 GMC S-15 Jimmy
- 1990–1996 Cadillac Fleetwood/Cadillac Brougham/Cadillac limousines
- 1990-2006 Holden Caprice
- 1990-2012 Holden Ute
- 1991–1992 GMC Syclone
- 1991–1992 Oldsmobile Custom Cruiser
- 1991-2004 Oldsmobile Bravada
- 1992–1993 GMC Typhoon
- 1993–2010 GMC Yukon
- 1994–1996 Chevrolet Impala SS
- 1994–1996 Buick Roadmaster
- 1995–2005 Chevrolet Blazer
- 1995–2005 GMC Jimmy
- 1996-2000 Isuzu Hombre
- 1999–2006 Cadillac Escalade
- 2002–2008 Chevrolet Avalanche
- 2002–2009 Chevrolet TrailBlazer
- 2002–2009 GMC Envoy
- 2003-2004 Chevrolet SSR
- 2003–2007 Hummer H2
- 2003–2008 Isuzu Ascender
- 2004–2007 Buick Rainier
- 2004–2012 GMC Canyon
- 2004–2006 Pontiac GTO
- 2005–2009 Saab 9-7X
- 2006-2008 Isuzu i-series
- 2006-2010 Hummer H3
See also
References
- ISBN 0-87938-267-8, p. 108
- ^ "700R4 Transmission Resource". 700R4 Transmission Resource. Retrieved 2016-06-27.
- ^ "General Motors transmissions". Retrieved 2022-12-31.
- ^ Chevrolet/GMC/Geo Transmission Lookup Table, http://www.autorepairmanuals.biz/site/573683/page/372807
- ^ Transmission Application Chart, "Transmission Application Chart". Archived from the original on 2008-01-01. Retrieved 2007-12-21.