Pontiac RWD Automatic Transmissions

There have been a number of Transmissions used in rear wheel drive (RWD)  Pontiacs. Hopefully, this page will be able to help someone out.

This article is broke down in to (3) sections:

GM Bellhousing Bolt Patterns (Chevy, Buick-Oldsmobile-Pontiac (BOP) and Dual Pattern)

Pontiac Rear Wheel Drive Automatic Transmission History

Rear Wheel Drive Automatic Transmission Identification.

-GM Bellhousing Bolt Patterns-

General Motors (GM) transmissions were cast with (3) different transmission bellhousing to engine bolt patterns:

Chevy Bolt Pattern – Above (left) is the “Chevy” Bolt Pattern. The high center peak at the top is it’s most notable feature. Transmissions with this bolt pattern will mate to most Chevy engines.

Buick-Olds-Pontiac (BOP) Bolt Pattern – Above (center) is the “BOP” (Buick-Olds-Pontiac) Bolt Pattern. The depressed flat at the top is it’s most notable feature. Transmissions with this bolt pattern will mate to most Buick, Cadillac, Oldsmobile and Pontiac engines. This pattern came in to use around 1963 on Buick’s, and 1964 on Pontiac’s.

GM Dual Pattern Bolt Pattern – Above (right) is the “Dual Pattern” bellhousing bolt pattern (the bolt holes are colored in for Chevy (blue) and BOP (red) to help clarify). It’s also been referred to as the “Universal” and “Corporate” pattern.

The lower two bolts and the locating dowels are in the same locations for both the “Chevy” and the “BOP” bolt patterns. The locations of the upper four bolts is different. The “Dual Pattern” takes advantage of this and provides for mating to either pattern without the use of an adapter plate.

It was used on a few different GM automatics like the TH350C (some, not all), and the TH2004R (most, except 60 degree “metric”/Cadillac Northstar). It first appeared in the mid to late 1960’s with the Super Turbine 300. The dual pattern bellhousings reappeared during the late 1970s on some TH350 when Chevrolet engines were optioned in some BOP and Cadillac automobiles when GM phased in corporate engines (usually the Chevrolet V8 or 90-degree V6) in lieu of division-specific engines. Aftermarket bellhousings by J.W. Performance Transmissions for GM engines incorporate the dual bolt pattern eliminating the need of a BOP to Chevrolet adapter plate.

Above is a Chevy bellhousing on the left, and a B-O-P bellhousing on the right. Note the matching bolt patterns on the back of the engine bl0cks behind them. The engine to the left is a Chevy 350, and the engine to the right is a Buick 350 (also shown below).

Buick-Oldsmobile-Pontiac transmission on the left – Chevrolet transmission on the right

TH350 with the ‘Dual Pattern’ bellhousing

-Pontiac RWD Automatic Transmission History-

Hydra-Matic (Hydramatic) 4-Speed Automatic (1948-1955):

In 1932, Cadillac had a group of engineers work on developing a shiftless transmission. During 1934, the Cadillac transmission group had developed a step-ratio gearbox that would shift automatically under full torque. This same group of engineers was then moved into GM Central Research, building pilot transmission units during 1935-36 which were then handed to Oldsmobile for testing. They initially developed the Automatic Safety Transmission (AST), which was a semi-automatic transmission that used planetary gears and a conventional friction clutch. The clutch was only needed to shift in and out of gear, but was not needed when shifting between the two forward gears.

The next design was the HydraMatic, which used hydraulic operation with a fluid coupling instead of the friction clutch. The transmission had (4) forward speeds (3.82:1, 2.63:1, 1.45:1, and 1.00:1) plus reverse, with all acceleration provided by gearing; its fluid coupling did not multiply the engine output as a torque converter does. This new transmission went into production in May 1939 for the 1940 model year, and were placed in Oldsmobiles. Oldsmobile produced more cars than Cadillac at the time, thus providing a better test base—and to protect the reputation of Cadillac in case of a market failure with the new transmission. In 1941, it became an option on Cadillac’s. In February 1942, passenger car production was halted due to the World War II.

Starting in 1948, the HydraMatic became optional for Pontiac’s (and was in 70% of them that year), although Buick and Chevrolet chose to develop their own automatic transmissions.

A massive fire destroyed GM’s HydraMatic plant in Livonia, Michigan on August 12, 1953. As a result, Pontiac used Chevrolet’s Powerglide to complete that year’s model year production. About nine weeks after the Livonia fire, GM opened up a new source for Hydra-Matic production at Willow Run, Michigan. By the time the 1954 models debuted in late 1953, Hydra-Matic production had returned to normal levels and all 1954 model Pontiac’s with automatic transmissions were once again equipped with Hydra-Matics.

GM’s HydraMatic plant on fire in Livonia, Michigan on August 12, 1953

Super Hydra-Matic (Super HydraMatic) 4-Speed Automatic 1956-1960:

GM’s Hydra-Matic underwent several revisions through 1955, before being gradually replaced by the substantially redesigned Super HydraMatic in 1956 (Also referred to as the “Controlled Coupling HydraMatic”, “Strato-Flight”, and the “Jetaway” in Oldsmobile)

The Controlled Coupling HydraMatic incorporated a secondary fluid coupling and a pair of sprag clutches in place of the former friction clutch and brake bands, shifting in part by alternately draining and filling the secondary coupling.

Roto Hydra-Matic (Roto Hydramatic) 3-Speed Automatic 1961-1964:

(Roto Hydra-Matic AKA “Slim Jim”)

In 1961, a somewhat less complex, but also far less reliable three-speed Roto Hydramatic (also referred to as ‘Slim Jim’) in which the “dump and fill” shifting principle was retained) was adopted and used in Pontiac’s full-sized Catalina, Ventura, and Grand Prix models, while all Cadillac’s and Pontiac’s Bonneville and Star Chief models retained the older four-speed “Controlled Coupling HydraMatic” unit. Hydramatic transmissions were ultimately replaced by a new three-speed torque converter automatic transmission called Turbo-Hydramatic in 1964 and 1965.

The Roto HydraMatic was more compact, providing only three forward speeds plus a small 8″ fluid coupling with a stator inside of the fluid coupling.

HydraMatic Division calls the Roto a four range, three gear HydraMatic. It counts the stator multiplication @ 3.50 to one as a first gear, and when road speed and the two coupling halves speed match, it counts the same gear with fluid now passing straight through the stator as 2nd gear at 2.93 to one. 2nd gear or third range has a ratio of 1.56 and because the fluid coupling is drained for this gear ratio making the front clutch apply makes this a rare automatic that is in FULL mechanical lock-up (coupling drained) in second gear. Fourth range the coupling fills releasing the front clutch makes a ratio of 1 to 1. This transmission, like single and dual range, and dual coupling hydramatics also have the feature of split torque in the transmission whereby in fourth or high gear only 40-to 50% depending on transmission, 40% in Roto’s case, but because of the design the coupling is only required to carry 40% of the engine torque. The rest is (60%) is in full mechanical connection making these hydramatics the most efficient automatic until the wide spread use of the lock-up torque converter.

Roto’s downfall was the 2-3 range or 1-2 gear change because it is not only a huge ratio jump from 2-3 range or 1-2 shift from 2.93 to 1.56, but also there is no fluid slippage in the coupling because the coupling drains (4 tenths of a second) to engage or apply the front clutch and so the trans goes to full mechanical connection. The other downfall of Roto HydraMatic was the extreme oil pressures in the small 8″ fluid coupling which caused transmission leaks. All HydraMatic transmissions suffer some shift quality with today’s ATF fluid as Type “A” fluid is not available. The main ingredient of Type “A” was banned years ago, however Japanese cars that have CVT automatic’s still use that ingredient in their special CVT fluid. That CVT fluid can only bought at the dealer. The ingredient is Whale oil.

The Roto Hydramatic was phased out after the 1964 model year in favor of the two-speed Super Turbine 300 and three-speed Turbo-Hydramatic.

Super Turbine 300 (ST-300) 2-Speed Automatic 1964-1969:

(Super Turbine 300)

The Super Turbine 300 (ST-300) was a two-speed automatic transmission built by General Motors. It was used in various Buick, Oldsmobile, and Pontiac models from 1964-1969.

The ST-300 had a three-element torque converter, a front and rear multiple-disc clutch pack, and a compound planetary gearset with a front band and a clutch pack for reverse and manual low gear. The unit was cooled with a small auxiliary oil cooler located beneath the engine radiator. It had a die cast aluminum case, and weighed 152 lb.

From 1967-1969, the ST-300 (not the Powerglide) was also available on the sporty Pontiac Firebird with the overhead cam in-line six-cylinder (230 and 250 cubic inches) or small V8 engines (326 and 350 cubic inches). Other Pontiacs would have included the Bonneville, Catalina, Grand Prix, LeMans, and Tempest

The ST-300 was discontinued entirely after the 1969 model year in favor of the TH400 and lighter TH350 Turbo-Hydramatic, the latter using the Super Turbine 300’s tailhousing.

Due to its two-speed with torque converter design, the ST-300 is often confused with Chevrolet’s Powerglide — which was also a two-speed torque converter transmission, but the ST-300 was of a completely different design and shared no parts with the Chevy unit, which had been around since 1950.

** The ST-300’s were the first GM automatics to incorporate multi-case (Dual Pattern) bellhousings (ST-300’s were bolted behind BOP powerplant’s along with the Chevrolet inline six) — which were later used with its successors — the THM350 and THM2004R overdrive.

Gear Ratios:

  • 1st: 1.76:1
  • High: 1.00:1
  • Reverse: 2.76:1

Chevrolet Powerglides:

Check out the Pontiac Poweglides for more information about Powerglide usage.

Pontiac TempestTorque TransAxle (Tempest Only) 1961-1963:

1961-1963 Pontiac TempestTorque, is actually a two speed transaxle. We generally think of transaxles as being in front wheel drive cars, but the 1961-1963 Tempest had an engine in the front, and used a flexible shaft drive inside a rigid torque tube that connected to the TempestTorque transaxle in the rear. This flexible shaft has been referred to by some as a “rope drive”. It was actually a 87.25-inch-long by .65-inch-diameter (with automatics) or 82.29-inch by .75-inch (with manual gearboxes) bar of forged SAE 8660 triple-alloy steel that was shot-peened, magnafluxed and coated with a flexible protectant. The shaft, located in a hollow box called a torque tube, arched just under three inches at its center, and it transmitted power to the rear transaxle like a torsion bar. The flexible shaft was designed with center bearings to absorb some of the vibrations inherent in the non-balance-shaft-equipped four-cylinder engines used in the Tempest.


As this transaxle image shows, the Pontiac Flex-Drive driveshaft always spins the torque converter at engine RPM, and then the power moves back into the Powerglide.

(click to enlarge)

Turbo Hydra-Matic 400 (TH400, or Turbo 400) 3-Speed Automatic 1965-1977:

(Turbo Hydra-Matic 400)

First introduced for the 1964 model year under the name “Turbo Hydra-Matic” in Cadillac’s and “Super Turbine” in Buick’s. The following year, application expanded to Oldsmobile and Pontiac (also referred to as Super Turbine 400 or ST-400) and to some full-sized Chevrolet’s.

The Turbo-Hydramatic or Turbo Hydra-Matic 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 Cadillac’s. 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. Through the end of the 1970’s substantially, more ‘BOP’ (Buick-Oldsmobile-Pontiac) bellhousing THM400’s were produced than any other THM400.

Many of the Buick, Cadillac, and Oldsmobile THM400’s produced between 1964-67 were equipped with a “Switch-Pitch” torque converter with a variable-pitch stator, which is sought after by collectors and drag racers. These can be identified outside the vehicle (with the torque converter removed) by a narrow front pump spline. Externally the switch pitch version has two electrical connections, where the non-switch pitch THM400 has only one.

As with other GM transmissions, GM changed the naming scheme of the TH400 in 1990 and it was then referred to as the 3L80 (3-speeds, Longitudinally positioned, 8000 lbs. GVW). An overdrive version of it was introduced as the 4L80-E. This electronically controlled transmission remains in production and wide use in heavy-duty GM and military applications.

** The TH400 was produced with either the Chevy or Buick-Oldsmobile-Pontiac bellhousing bolt patterns. It was not built with the ‘Dual Pattern’ bellhousing bolt pattern.

The Turbo Hydra-Matic 400 was used in the:

  • 1974-1977 Pontiac Bonneville
  • 1974-1977 Pontiac Catalina
  • 1967-1976 Pontiac Firebird
  • 1969-1977 Pontiac Grand Prix
  • 1972-1977 Pontiac LeMans
  • 1967-1971 Pontiac Tempest

Gear Ratios Are:

  • 1st: 2.48:1
  • 2nd: 1.48:1
  • 3rd: 1.00:1
  • Reverse: 2.07:1

Turbo Hydra-Matic 350 / 350C (TH350, or Turbo 350) 3-Speed Automatic 1969-1983:

(Turbo Hydra-Matic 350)

The TH350 transmission 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 TH350 has been manufactured by Buick in its Flint, Michigan, plant and by Chevrolet in the Toledo, Parma (Ohio), and Windsor, Ontario plants. Both Chevrolet and Buick divisions produced the THM350.

The Turbo 350 quickly become known for its strength, versatility and compactness. They were prevalent in nearly all GM, rear-wheel-drive cars and trucks through 1984, and were typically paired with Small Block V6 & V8 engines. It was phased out of use and superceded by GM’s 700R4 starting in 1982.

TH350C – 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, this transmission was phased out in 1984 in GM passenger cars for the 700R4.

The TH350 was produced with the Chevy, BOP, and Dual Pattern bellhousing configurations.

The Turbo Hydra-Matic 350 was used in the:

  • 1974-1983 Pontiac Bonneville
  • 1974-1980 Pontiac Catalina
  • 1969-1981 Pontiac Firebird
  • 1976-1983 Pontiac Grand Prix
  • 1972-1981 Pontiac Lemans
  • 1977-1979 Pontiac Phoenix

Gear Ratios Are:

  • 1st: 2.52:1
  • 2nd: 1.52:1
  • 3rd: 1.00:1
  • Reverse: 2.07:1

Turbo Hydra-Matic 200 / 200C (Turbo 200) 3-Speed Automatic 1976-1987:

Right after the 1973 OPEC oil embargo, GM developed a lighter-duty version of the THM350 with lightened materials — primarily alloys in place of ferrous materials (e.g. clutch drums and oil pump), the Turbo-Hydramatic 200. The THM-200 was first used in 1976 models including GM’s T-cars, X-cars, and some Isuzu. However, this transmission was notorious for its failure rate when used behind too large of an engine – the largest displacement being the Oldsmobile 5.7L Diesel. No multicase (dual pattern) bellhousings were used – bellhousing patterns included Chevrolet V8, Buick-Oldsmobile-Pontiac, Vega 4, GM 60 degree pattern (includes the Tech IV), and Isuzu G engine.

TH200C – Around 1979, 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. This revised THM-200 was referred to as the THM-200C

Pontiac’s that used the TH200 & TH200C:

  • 1977-1986 Pontiac Bonneville (TH200C)
  • 1977-1981 Pontiac Catalina (TH200, TH200C)
  • 1980-1983 Pontiac Firebird (TH200C)
  • 1977-1987 Pontiac Grand Prix (TH200C)
  • 1978-1981 Pontiac Lemans (TH200C)
  • 1983-1986 Pontiac Parisienne (TH200C)
  • 1977-1979 Pontiac Phoenix (TH200C)
  • 1976-1977 Pontiac Ventura (TH200C)

The gearing for the THM200C is:

  • 1st: 2.74:1
  • 2nd: 1.57:1
  • 3rd 1.00:1
  • Reverse: 2.07:1

Turbo Hydra-Matic 250 (TH250 or Turbo 250) 3-Speed Automatic 1976-1984:

(Turbo Hydra-Matic 350)

The THM250 is a derivative of the TH 350 and was introduced in 1974 in Chevrolets as a Powerglide replacement. Internally, the THM250 is a TH 350 without the intermediate clutch pack. Instead, it has a band adjuster similar to the Powerglide. After being phased out for the TH200/200C. It was reintroduced in 1979 as the THM250C in the wake of the failure-prone THM200/200C.

Pontiac’s that used the THM250 are:

  • 1980-1984 Pontiac Grand Prix
  • 1976-1977 Pontiac Sunbird

Gear Ratio for the TH250 and 250C:

  • 1st: 2.52.1
  • 2nd: 1.52.1
  • 3rd: 1.00.1
  • Reverse: 2.07.1

Turbo Hydra-Matic 200-4R (200R4) 4-Speed Automatic 1981-1989:

(Turbo Hydra-Matic 200-4r or “200R4”)

For the 1981 model year, the 200-4R (sometimes called 200R4) was introduced. The components which were prone to failure in the THM200 were improved, and in the later 80’s this transmission was used with high-power applications — primarily the Buick Grand National. The 200-4R was configured with several different torque converters and gear ratios depending on the vehicle application.
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 similar to the TH-350 (overall length, drive shaft yoke spline count/diameter and general size), 200-4Rs are often swapped in place of TH-350s in older vehicles to provide an overdrive gear.

The TH-200-4R has a 2.74:1 first gear ratio, and overdrive is 0.67:1. Its odd-shaped 16-bolt pan has 13mm bolt heads. The TH-200-4R was used in GM rear-wheel-drive cars equipped with the 231 Buick, 301 Pontiac, and the Oldsmobile 307, 350 gas and 350 diesel engines from 1981-’90; however, many Chevrolet 267 and 305 V-8s also used the TH-200-4R because of the multi-fit bellhousing. You can find a donor TH-200-4R in one of these cars:

  • 1981-1990 Cadillac Fleetwood, de Ville and Brougham
  • 1981-1988 Buick LeSabre, Electra RWD, Chevelle, Monte Carlo, Malibu and El Camino
  • 1982-1990 Chevrolet Impala, Caprice, Olds Delta 88, 98 and Custom Cruiser
  • 1984-1987 GMC Caballero and Pontiac Grand Prix
  • 1983-1988 Olds Cutlass 442 and Supreme
  • 1983-1989 Pontiac Bonneville, Parisienne and Safari Wagon
  • 1981-1987 Buick Regal
  • 1981 Buick Century and Pontiac Firebird with 301

The transmission identification is on a plate on the right side of the case towards the tailshaft. This ID plate is attached by one rivet. The plate will have a two- or three-letter transmission code in large letters.

The most desirable TH-200-4Rs for performance enthusiasts are the units manufactured for Buick Grand National, Olds 4-4-2 and Chevy Monte Carlo SS in 1986-’87. These units used a special valve body. They also had a larger reverse boost valve, second to third intermediate servo, and a specially designed governor assembly. Their BQ, OZ, CZF, KZF or BRF transmission codes can identify these more desirable units.

This transmission is ideal for swapping with a TH-350 or a Powerglide, because the overall length and the bell housing bolt pattern of the TH-200-4R are the same, and your original driveshaft does not have to be shortened. The output shaft is 27-spline, the same as the TH-350’s. Moving the crossmember will be necessary, because the TH-200-4R crossmember is mounted on the extreme end of the tailshaft.
When exchanging the TH-350 with the TH-200-4R, the existing TH-350 detent cable should be changed to a 200-4R adjustable type. Usually the engine computer activates the torque converter lockup; however, an aftermarket lockup adapter can be purchased for non-computerized vehicles. Toggle switch lock-ups can be made to replace the lock-up adapter, but we recommend the pre-made lockup adapter to make the exchange look a lot more professional. The lock-up should always be used when performing this changeover or the torque converter will slip too much, which can lead to early transmission failure.

** The GM 200-4R transmissions were made with the ‘Dual Pattern’ bellhousing bolt pattern.

Gear Ratios Are:

  • 1st: 2.74
  • 2nd: 1.57
  • 3rd: 1.00
  • 4th: 0.67
  • Reverse: 2.07

Turbo Hydra-Matic 700R4 (TH700R4, 4L60, 4L60E, 4L65E, 4L70E) 4-Speed Automatic:

(Turbo Hydra-Matic 700-R4)

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 an ECU to shift. 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 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.

** The GM 700R4, 4L60, 4L60-E, and 4L65-E transmissions were NOT made with a Buick-Pontiac-Oldsmobile bellhousing bolt pattern, or a ‘Dual Pattern’ bellhousing that will bolt to a Pontiac engine block.

Pontiac’s that use these transmissions are:

  • 1983-1989 Pontiac Firebird (700R4)
  • 1990-1993 Pontiac Firebird (4L60)
  • 1994-2002 Pontiac Firebird (4L60-E)
  • 1984-1988 Pontiac Parisienne (700R4)
  • 2004-2006Pontiac GTO (4L65-E)

Gear Ratios:

  • 1st: 3.059
  • 2nd: 1.625
  • 3rd: 1.000
  • 4th: 0.696
  • Reverse: 2.294

Max Gearbox Torque: 670 ft-lbs

GM Hydra-Matic 5L40-E 5-Speed Automatic 2006-2008:

(Hydra-Matic 5L40-E)

The 5L40-E (and similar 5L50) are a series of automatic transmissions made by General Motors. Designed for longitudinal engine configurations (RWD), the series includes 5-forward gears and is used in the GM Sigma platform vehicles from Cadillac, the Pontiac Solstice, Pontiac G8, and Holden Commodore.

The electronically controlled transmission is designed around a fully articulated Ravigneaux gearset that is controlled by electronically timed application of several range-specific hydraulic clutches, in combination with mechanical one-way sprag clutches. The 5L40E unit’s centerpiece is an automatic overdrive which supersedes the French-made 4L30E four-speed automatic light-duty gearboxes, and like them features a torque converter clutch to eliminate slipping losses in select forward ranges. It is assembled in Strasbourg, France.

The 5L40/50 series was replaced starting in 2007 with the 6L50 six-speed.

** The GM 5L40 transmissions were NOT made with a Buick-Pontiac-Oldsmobile bellhousing bolt pattern, or a ‘Dual Pattern’ bellhousing that will bolt to a Pontiac engine block.

Pontiac’s that use this transmission are:

  • 2006 Pontiac Solstice (5L40-E)
  • 2008-2009 Pontiac G8 (5L40-E)

Gear Ratios:

  • 1st: 3.42
  • 2nd: 2.21
  • 3rd: 1.60
  • 4th: 1.00
  • 5th: 0.75
  • Reverse: 3.02

Max Gearbox Torque: 494 ft-lbs

GM Hydra-Matic 6L80 6-Speed Automatic 2008-2009:

(Hydra-Matic 6L80)

The Hydra-Matic 6L80 is the first member of a new family of fully automatic, six-speed, clutch-to-clutch, rear wheel drive, electronic-controlled transmissions that General Motors will be offering. The transmission consists primarily of a four-element torque converter, an integral fluid pump and converter housing, a single and double planetary gear set, friction and mechanical clutch assemblies, and a hydraulic pressurization and control system.

The four-element torque converter contains a pump, a turbine, a pressure plate splined to the turbine, and a stator assembly. The torque converter acts as a fluid coupling to smoothly transmit power from the engine to the transmission. It also hydraulically provides additional torque multiplication when required. The pressure plate, when applied, provides a mechanical “direct drive” coupling of the engine to the transmission.

The planetary gear sets provide the six forward gear ratios and reverse. Changing gear ratios is fully automatic and is accomplished through the use of a Transmission Control Module (TCM) located inside the transmission. The TCM receives and monitors various electronic sensor inputs and uses this information to shift the transmission at the optimum time.

The TCM commands shift solenoids and variable bleed pressure control solenoids to control shift timing and quality. The TCM also controls the apply and release of the torque converter clutch which allows the engine to deliver the maximum fuel efficiency without sacrificing vehicle performance. All the solenoids, including the TCM, are packaged into a self-contained control solenoid valve assembly.

** The GM 6L80 transmissions were NOT made with a Buick-Pontiac-Oldsmobile bellhousing bolt pattern, or a ‘Dual Pattern’ bellhousing that will bolt to a Pontiac engine block.

Pontiac’s that use this transmission are the:

  • 2008-2009 Pontiac G8 GT / GXP (6L80)

Gear Ratios:

  • 1st: 4.027
  • 2nd: 2.364
  • 3rd: 1.532
  • 4th: 1.152
  • 5th: 0.852
  • 6th: 0.667
  • Reverse: 3.064

-Pontiac RWD Automatic Transmission Identification-

If you can’t visually identify a transmission by its case, many people recommend identifying transmissions by their pans and the number of bolt holes. Below is a photo of various transmission pans and their identification.

Typical application information:

GM Transmission Dimensions:

Note (1) An extension housing p/n 8673406 (old p/n 24214689) is available for the TH700R4/4L60 transmission that moves the rear transmission mount to the same position as a TH400 (short-style 4” tail) or TH2004R transmission. This 7-3/8” long extension housing can eliminate transmission crossmember modifications when replacing a TH400 or TH2004R transmission with a 4L60 assembly.


(Click the photos to enlarge)

Roto Hydra-Matic (Roto Hydramatic) 3-Speed Automatic 1961-1964:

Super Turbine 300 (ST-300) 2-Speed Automatic 1964-1969:

This ST-300 left side view shows the electrical connector near the rear of the transmission which depicts this as a “switch pitch” style of transmission. Pontiac did not use the “switch pitch” ST-300, but Buick and Oldsmobile did. The “switch pitch” used a variable pitch torque converter that could change stall RPM with an electric solenoid inside the transmission. The solenoid was activated by a switch usually mounted on the throttle linkage. We’ve included this information for anyone hunting for a ST-300.

One positive method to identify this transmission is to notice the fluid port on the stator support shaft. The proper matching Torque Converter will have the corresponding bushings inside the Torque Converter that creates the fluid channel. This fluid channel allows the pressurized transmission fluid to change the pitch of the vanes.

Here is a look at the 14-bolt transmission pan. You’ll note that it’s shaped much different than the Powerglide’s 14-bolt pan. Also, it’s similar to the Turbo 350 3-bolt pan, but in addition to having one more bolt than the Turbo 350, it also angles on (2) corners and not one.

Turbo Hydra-Matic 400 (TH400, or Turbo 400) 3-Speed Automatic 1965-1977:

Turbo Hydra-Matic 350 / 350C (TH350, or Turbo 350) 3-Speed Automatic 1969-1983:

Turbo Hydra-Matic 250 (TH250 or Turbo 250) 3-Speed Automatic 1976-1984:

The Turbo 250 is very similar to the Turbo 350 in appearance, and even uses the same 13-bolt transmission pan. The visual difference to look for is the ban adjusting bolt on the passenger side of the block as shown in the photo below.

Turbo Hydra-Matic 200 / 200C (Turbo 200) 3-Speed Automatic 1976-1987:

Turbo Hydra-Matic 200-4R (200R4) 4-Speed Automatic 1981-1989:

The 200-4R will have a plug connection for the lock-up torque converter on the drivers side that points straight out.

Turbo Hydra-Matic 700R4 (TH700R4, 4L60, 4L60E, 4L65E, 4L70E) 4-Speed Automatic:


The 700R4 transmission will have a torque converter lockup connection plug connection on the drivers side that points up.