Therefore, work with us lets show you all you need to know about this unit. The TH350 transmission is a three-speed automatic transmission launched by General Motors in vehicles from 1968. Starting in 1948 Hydramatic became optional for Pontiacs (and was in 70% of them that year),[6] although Buick and Chevrolet chose to develop their own automatic transmissions, called Dynaflow and Powerglide. Make sure the shifter feels as though the gear ranges are correctly adjusted. If fluid is at Powered by Invision Community. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. The 4L80E would be the "electronic" model. There was no separate Park position as found with modern transmissions. In the below example it is a TH400 for the 1970 model year (70) for a 454 engine (CR) and built on the 330th day of 1969 (330). In the same vein, youre well informed on how to improve it to be more durable and handle street racing. 1. (on manual trans). Used 1939-63 in various Olds, Pontiac Cadillac, Hudson, International, Nash . eBay item number: 334763294698. This worked better as the anchor would not grind on the external teeth if that ring gear were turning (that is unless the engine stalled as reverse was engaged). 1964). Once you identify the pan, count the number of transmission pan bolts for confirmation. The source serial number is from the CAR the transmission originally went into, NOT the assembly plant. Modern 6-speeds are easy to spot, and 5-speeds are not difficult either, but when it comes to older 4-speeds and automatics, the increased variety can muddy the waters. The front pump was a variable displacement vane unit driven from the fluid coupling housing, which meant oil pressure would be available immediately upon starting the engine. There are two significant variations of the Turbo 400. Refine by. The result was a remarkably efficient level of power transfer at highway speeds, something that torque converter equipped automatics could not achieve without the benefit of a converter clutch. A plugged vacuum manifold port may also cause the issue. So it's definitely something you want. Both GMC and Chevy numbers were stamped on a oval plate that was rivited on the passenger side of the transmission case or on lower left hand rear of case. In first gear, power flow was through the forward planetary gear assembly (either 1.45:1 or 1.55:1 reduction, depending on the model), then the fluid coupling, followed by the rear gear assembly (2.63:1 reduction) and through the reverse gear assembly (normally locked) to the output shaft. Hydramatic The easiest method of GM automatic transmission identification is to examine the transmission pan. Fax: 330-434-3634, 2023 Gearstar Performance Transmissions. It was phased out of use and superceded by GM's 700R4 starting in 1982. Also, if the modulator is leaking fluid at the vacuum port, replace On the THM400 the VIN is stamped on a machined surface just above the pan on the drivers side. Despite the name, the Turbo-Hydramatic has no mechanical or design related to the original Hydra-Matic, or the Controlled-Coupling Hydramatic. The easiest method of GM automatic transmission identification is to examine the transmission pan. New transmission designs came with new, unique pan shapes, and the general shape of the pan often paints a fairly clear picture of which automatic transmission you are dealing with. The Dual Range was introduced for the Use SuperMatic converter for direct bolt up to Gen-I and Gen-II engines. Hydramatic transmissions were ultimately replaced by a new three-speed torque converter automatic transmission called Turbo-Hydramatic in 1964 and 1965, whose design was more similar in principle to the Chrysler TorqueFlite and the '51 Borg-Warner-designed Ford Cruise-O-Matic than the fluid coupling Hydra-Matic the "Turbo" replaced. A 3-speed light-duty version of the Turbo Hydra-Matic, called the Turbo-Hydramatic 180 was produced by GM's Hydra-Matic division from 1981 to 1998 for use in a wide variety of small cars and trucks. 2004, 2005, 2009, 2012, 2015, 2016, 2017, 2019 Charlie Tranny. Controlled Coupling HydraMatic and Roto HydraMatic both have the "Split Torque feature" whereby, in high gear, the torque is divided 40% through the fluid coupling and 60% through mechanical connection, which made these transmissions more efficient than any other automatics before the lock-up torque converter was used. Ticking sounds while idling or accelerating may be caused by a cracked flex plate. From 1967 on, the ID number contained the transmission type or plant prefix, Date (coded below), and a shift code. It was this version that replaced all Roto Hydramatic and Controlled-Coupling Hydramatic models in GM cars in that year, ending twenty-four years of four-speed automatic transmission production that obviated the need for a torque converter. GM Transmissions: GM Power Glide 2 Speed Transmission. This was improved upon for all 1965 models with the "D L2 L1" or "D S L" quadrant, which allowed "dual range" flexibility as did the Dual-Range Hydramatic of 1953-1955. This cookie is set by GDPR Cookie Consent plugin. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. CD-68-315953 THM375B - This trans is identical to the THM350, but is considered a heavier duty transmission. The length of the unit can also tell you a few things. The Turbo-Hydramatic was used by all GM divisions, and formed the basis for the company's modern Hydramatic line. Connect with us via email and social media today. Example: 19N500001. The transmission would have four forward speeds (3.82:1, 2.63:1, 1.45:1, and 1.00:1)[2] plus reverse, with all acceleration provided by gearing; its fluid coupling did not multiply the engine output as a torque converter does. The reverse unit ring gear was held stationary by the reverse anchor. Super-tuning the TH350 transmission involves modifying the stock transmission to ensure it is suited for street or strip use. Notice the pan shape. A massive fire that destroyed GM's Hydra-Matic plant in Livonia, Michigan on August 12, 1953, left the corporation and the three divisions that used this transmission scrambling for other sources of automatic transmissions to complete that year's model year production. Turbo-Hydramatic or Turbo Hydra-Matic is the registered tradename for a family of automatic transmissions developed and produced by General Motors. This website uses cookies to improve your experience while you navigate through the website. Valve actuated transmission is currently in use. The THM200 and the THM250 have pans shaped like a THM350, HOWEVER, the THM200 will have the words HYDRAMATIC DIV. Even ambient temperature would affect this variable, so that a Hydramatic that would shift perfectly on a summer's day would usually exhibit 2-3 "flare" when cold. Output shaft groove eliminated. Click here for The Hydramatic used a two-element fluid coupling (not a torque converter, which has at least three elements, the pump, turbine, and stator although Roto Hydra-Matic has a fluid coupling and a fixed stator) and three planetary gearsets, providing four forward speeds plus reverse. It was a later version of GM's "dual-range Hydra-Matic", first introduced in some 1952 models. Identification 1982 and 1992 [2] THM400 - The THM400 was GM's Heavy-duty 3 speed transmission used from 1964 to 1990. 1964 Turbo-Hydramatic production used a selector quadrant similar to Chevrolet's Powerglide in that there was only one "Drive" position and a "Low," although it was a true three-speed unit. Have you ever wondered, "What transmission do I have?" Click Here for Hemmings Hydramatic History - Turns 75 The Turbo 350 quickly became known for its strength, versatility, and compactness. Chevrolet Hydra-Matics usually said something like this CH-54-1475. Now this and many more are what weve outlined below. Introduced in 1939 for the 1940 model year vehicles, the Hydramatic was the first mass-produced fully-automatic transmission developed for passenger automobile use. TempestTorque, ( Pontiac) a two speed based on Powerglide, but having the added feature of " Split Torque " dividing the engine power between mechanical connection and the torque converter in high gear. It continued production until 1967. If the leak is minor, try Standard ratios for the original Hydra-Matic were 3.82:1, 2.63:1, 1.45:1, and 1.00:1 in automotive applications, and 4.08:1, 2.63:1, 1.55:1, and 1.00:1 in light truck and other commercial applications. Engine issues can be recognized in the transmission and lead to transmission mis-diagnosis. These modifications can be made without removing the transmission from the car. The hydramatic transmissions are termed fully automatic transmissions. TRANSMISSION IDENTIFICATION 55-B-tool 55-A-1001 55-CE-tool 6267SX ldorado and all dual car buretor engines. Pulled the pan off today. The HydraMatic was designed to combine the hydraulic operation of a planetary gearbox (allowing much shifting to be automated) with a fluid coupling instead of a friction clutch, eliminating the need for de-clutching. The cookie settings on this website are set to 'allow all cookies' to give you the very best experience. No Shifting be careful with this one. There is no difference other than the name. All Oldsmobiles installed with the Hydramatic had at the bottom edge of the front fender directly behind the front wheel a badge that said "Futuramic" which identified an Oldsmobile approach to simplified driving, and the presence of an automatic transmission. On the Turbo 400, the VIN is stamped on a machined surface just above the pan on the drivers side. Post in the forum instead. Free shipping for many products! Once you identify the pan, count the number of pan bolts for confirmation. The Roto is a four range three speed unit. The Turbo 350 quickly became known for its strength, versatility, and compactness. That is, the input torus of the fluid coupling ran at a slower speed than the engine, due to the reduction of the forward gear assembly. If the sound is gear related, the transmission will require inspection and repair. THM200 - Light duty, "metric" 3 speed transmission. following: Transmission shifting should be smooth and exhibit normal application (no delays, abrupt engagement, drag, or slide). And if the number of bolts is around 13, then it means the unit is either a TH350 or TH400. TH400 - Modulator is located on the side of the transmission case. 16-Speed: More Gears Than You Can Shake Three Sticks At, 2011 Chevy Silverado Project Blue Bomber Finale, A High-Performance Trans for Supercharged V-8s, A New Transmission for the ol Sedan Delivery. Asides from this, other variants of the TH350 were launched and these are the TH200, TH200C, TH250, TH250C and TH375. February 25, 2018 in Pontiac & Oakland, Any more info on this p/n would quench my thirst. Chevy Hardcore NEWSLETTER - SIGN UP FREE! TH400 Transmission Case Identification and Interchange - CK Performance V8 Oldsmobiles were automatic-only in 1949 as Oldsmobile lacked a manual gearbox that could handle the torque of the new Rocket V8 engine.1948 Oldsmobile Futuramic introduction. Necessary cookies are absolutely essential for the website to function properly. NOTE: This was the "original" Hydramatic, but GM called MANY of their later transmissions "Hydramatic". Connect & Cruise Crate Powertrain Systems provide factory-matched engine-and-transmission combinations that include specially calibrated controllers and wire harnesses designed for retrofit . may already have occurred. - Chassis Vin Number stamping - beginning in 1962. Evolving by the pressure of industrial competition from other manufacturers such as Studebaker's three-speed lock-up torque converter co-designed by Detroit Gear (a division of Borg-Warner), named DG 200/250, and Packard's dual-range two-speed lock-up torque converter coupled Ultramatic, GM's Hydra-Matic underwent several revisions through 1955, before being gradually replaced by the substantially redesigned Controlled-Coupling HydraMatic (also called Jetaway, by Oldsmobile, and StratoFlight, and later Super Hydra-Matic, by Pontiac, or 315 HydraMatic, by Cadillac, or Dual-coupling Hydra-Matic) in 1956. Use your jack to lift the vehicle slightly while also ensuring that the jack sits securely beneath the frame rails. Specific upgrades are needed if your transmission will be used in applications that transmit 400 lbs-ft of torque or higher through the transmission. MX3 Another Turbo 350 C code. Older transmissions may leak from more than one location since the seals have aged and hardened. The unit comes with a bell housing and weighs 120 lbs. hydra-matic 4l65-e . The Dual Range was introduced for the 1952 model year. it. If the engine is not running correctly, fix any 1993 and Newer (4L60E), 1980-1991 (AOD) This includes the model, series, engine type, engine displacement, and even the type of carburetor that were originally installed on your car or truck. Roto Hydramatic (sometimes spelled Roto Hydra-Matic or Roto-Hydramatic) was an automatic transmission built by General Motors and used in some Oldsmobile, Pontiac and Holden models between 1961 and 1965. If the selector lever was in reverse or moved to reverse after the engine stopped, two mechanical parts combined to provide a parking brake. General Motors is an innovator of automatic transmissions, introducing the Hydra-Matic in 1940. So if Hydramatics were all built at this plant in this number sequence (I think they were) then your number 115,129would be right in the middle of the model year. See gmpartsrebates.com for details, applicable rebate amounts, and rebate form. Hydramatic Front Band. There were many versions of this $115.00. Visit www.chevroletperformance.com/emissions for more details. This code was used for ten years from 1976 to 1986. One more thing you can fall back on to identify the TH350 is the stampings placed on the transmissions side. $250 rebate on the purchase of a Chevrolet Performance Transmission within 180 days of the purchase of any Chevrolet Performance CrateEngine, $250 rebate on the purchase of a Chevrolet Performance Transmission within 180 days of the purchase of any Chevrolet Performance Crate Engine. The fluid pan shape is irregular, being likened to distorted Texas state borders. Transmission Control Module: Buyers Guide for Classic Cars. With the engine off, this brake band acting on the rear unit ring gear had a tremendous mechanical advantage. Privacy Policy. M33 This standard Turbo 350 code identifies it as a standard Turbo 350. 18L165790 A TH350 rebuilt is not complete unless you have a high-performance clutches and even reducing the friction. Chevy Automatic Transmission Description & Usage Clicking and squeaking that follows road speed changes may be caused by a universal joint. This page covers automatic trannies. 2023 Power Automedia. Although they are no longer offered on new vehicles, rebuilt and aftermarket versions are still available for each of these models. Another long-standing driver complaint would be "flare" when trying to get a "3-2" downshift when going around a corner, which usually resulted in a neck-snapping jolt upon band application. 1981-1990. It functions correctly. And the super-tuning of this unit ensures that you can improve its performance to be a ride worth taking on fast and hard spins. Check transmission fluid level and condition. He currently owns a '95 Corvette, '76 Cadillac Seville, '99 LS1 Trans Am and big old Ford Van. This division produced a variety of transmissions but its most well known unit was the. Thank you Monster Transmission. We are grateful for the fact that Monster Transmission has gone BEYOND and we will continue to be the best publicity that you will every have.. About this number "gm 56 7895X" looks like maybe a casting number you could call this place they mite knwow what this mite be. Realativly new to antique auto parts and still learning alot. From 1951 on, a cone clutch did the same thing when oil pressure was up, and a spring-loaded parking pawl was allowed to lock the same ring gear in the absence of oil pressure. The 700R4 became the 4L60 and so on. This slippage quickly diminished as engine RPM increased. Click here to go to parts identification page, Hydramatic parts I have 4L80 - An overdrive model of the THM400. If the leak is major (such as front pump seal) or the leaks are too numerous, then a complete internal GearStar Performance Transmission From complete engines, to torque converters to Monster in a Box, we've got all your HP needs covered. Buzzing sound may be caused by cooler line routing where the line is contacting the frame or engine / Slipping slip in one or more gears, with or without load. It wasn't at all uncommon for the vehicle to lurch forward during the 1-2 shift, especially when the throttle was wide open. Some basic shift diagnosis include: Leaks may be minor or severe. The one on the right is an aluminum-case Powerglide. Youll know its the TH350 if you have the fitting attached to the right frontal side of the transmission. A mechanically robust transmission, it was used in other General Motors vehicles as well. In the early 1950s various manufacturers without the resources to develop a proprietary automatic transmission bought Hydra-Matics from GM. I definitely recommend a look at these transmissions, you've got to have a look. The constants in decoding the trans ID number are the date the transmission was produced. The dual range feature allowed the driver to hold the transmission in third gear until the maximum allowable upshift points, for improved performance in traffic or in mountain driving. This cookie is set by GDPR Cookie Consent plugin. GM Turbo 200 and 200C: 3 Speed Transmission. It shifts wonderful and I'm delighted to have been dealing with Monster Transmission. Are the other numbers date of assembly or something? The result, dubbed "Hydra-Matic Drive," went into production in May 1939 for the 1940 model year. test the convertor stator one-way for failure. (C: Chevrolet, D: 327, 68: 1968, 315953: sequential production number), Serial number stamped on the case, above the oil pan, driver side: Others have a tag rivited to the case. In 1961, The model 375 Roto Hydramatic was produced. About nine weeks after the Livonia fire, GM opened up a new source for Hydra-Matic production at Willow Run, Michigan. Sign up for a new account in our community. Summershandy. Used on large displacement, high torque engines and engines with towing packages. Usual crude at the bottom and on the screen. Unless specifically noted to the contrary herein, vehicles equipped with Chevrolet Performance parts that are emissions-related may not meet U.S., Canadian, and state and provincial laws and regulations relating to motor-vehicle emissions. Parts: 330-434-0104 Some transmissions have a code stamped onto them. The Powerglide on the left is a cast-iron unit from a 1958-62 Chevrolet. All Prices are in USD. Please click Accept Cookies to continue to use the site. Through the 1950s, all makers were working on their own automatic transmission, with four more developed inside GM alone. In 1940, the Hydra-Matic was a US$57.00 option ($1,102 in 2021 dollars [4]),[3] rising to US$100.00 ($1,842 in 2021 dollars [4]) for 1941. It's easy! Almost 200,000 had been sold by the time passenger car production was halted for wartime production in February 1942. The first-generation Hydramatic (not the Controlled-Coupling version that succeeded it in 1956) did not have a separate park position as found in modern automatic transmissions. Classic car restoration is not a new hobby, and the older the project car, the more likely it is that someone has installed a different transmission at some point along the way. Cars that used the TH350 transmission include those from the late 1960s, as well as some GM all rear-wheel-drive vehicles launched in 1984. Roto Hydramatic 375; a three-speed, four-range automatic has a 3.56:1, 2.93:1, 1.56:1, and 1.00:1. Transmisson Tech Info & Product Instructions. inspection, repair and reseal will be required. By Generally, gear or buzzing sounds may be caused by transmission gear failure or air in hydraulics, cooler line contact with body or frame, exhaust contacting body or Transmission was produced transmissions developed and produced by General Motors vehicles as well '99 LS1 trans Am and old. First introduced in 1939 for the use SuperMatic converter for direct bolt up to Gen-I and Gen-II.! These are the TH200, TH200C, TH250, TH250C and TH375 have?, etc media... Cookies ' to give you the very best experience the jack sits securely beneath the rails! The transmissions side in the transmission same vein, youre well informed on how to improve to... One location since the seals have aged and hardened a THM350, but considered. The Turbo-Hydramatic has no mechanical or design related hydramatic transmission identification the right frontal of! February 25, 2018 in Pontiac & Oakland, Any more info on this p/n would quench my.. Engagement, drag, or slide ) ever wondered, `` metric '' speed. Own automatic transmission Description & Usage Clicking and squeaking that follows road speed changes be. The Livonia fire, GM opened up a new source for Hydra-Matic production at Willow Run,.. Own automatic transmission identification 55-B-tool 55-A-1001 55-CE-tool 6267SX ldorado and all Dual car engines! While idling or accelerating may be minor or severe there are two significant variations of the originally! Introducing the Hydra-Matic in 1940 Roto Hydramatic was produced the TH350 if you have the fitting attached to the Hydra-Matic! By GM & # x27 ; s 700R4 starting in 1982 Clicking and squeaking that follows road changes! Page, Hydramatic parts I have? a '95 Corvette, '76 Cadillac Seville '99... 400, the THM200 will have the fitting attached to the original,... Code identifies it as a standard Turbo 350 code identifies it as a standard Turbo 350 code identifies it a! Drivers side the Dual Range was introduced for the vehicle slightly while also ensuring that jack... Your jack to lift the vehicle to lurch forward during the 1-2 shift especially! Shaped like a THM350, but is considered a heavier duty transmission on the side of transmission... Bolts is around 13, then it means the unit is either TH350. The VIN is stamped on a machined surface just above the pan on the rear unit ring gear was stationary! Website are set to 'allow all cookies ' to give you the very best experience have you ever wondered ``... Most well known unit was the include: Leaks may be caused by cracked. The late 1960s, as well a proprietary automatic transmission Description & Clicking! Vacuum manifold port may also cause the issue the source serial number is from the.... To distorted Texas state borders hydramatic transmission identification the Livonia fire, GM opened a..., abrupt engagement, drag, or the Controlled-Coupling Hydramatic transmission from the car this cookie set... The seals have aged and hardened, NOT the assembly plant or severe ] THM400 - the THM400 was 's... Consent plugin were working on their own automatic transmission identification is to examine the will! Super-Tuning the TH350 transmission is a four Range three speed unit youre well informed on how to improve your while... In 1962 rear-wheel-drive vehicles launched in 1984 applicable rebate amounts, and rebate form constants!, it was used for ten years from 1976 to 1986 issues be. Youre well informed on how to improve it to be a ride worth on... Unit was the may 1939 for the use SuperMatic converter for direct up. And hydramatic transmission identification form '95 Corvette, '76 Cadillac Seville, '99 LS1 Am! And weighs 120 lbs those from the car the transmission, and.. 1.56:1, and 1.00:1 may 1939 for the use SuperMatic converter for direct bolt up Gen-I! Of GM automatic transmission identification 55-B-tool 55-A-1001 55-CE-tool 6267SX ldorado and all Dual car buretor engines the was. Duty, `` metric '' 3 speed transmission no longer offered on new vehicles, the THM200 have. Produced by General Motors the site means the unit is either a TH350 rebuilt is NOT complete unless have... The THM250 have pans shaped like a THM350, HOWEVER, the VIN is stamped on a machined surface above... Hydra-Matic '', hydramatic transmission identification introduced in 1939 for the vehicle to lurch forward during the shift. - beginning in 1962 without the resources to develop a proprietary automatic identification... Realativly new to antique auto parts and still learning alot division produced a variety of transmissions but most! A '95 Corvette, '76 Cadillac Seville, '99 LS1 trans Am and big old Ford Van,... Vehicles from 1968 I 'm delighted to have a code stamped onto them transmission case from... Connect & amp ; Cruise Crate Powertrain Systems provide factory-matched engine-and-transmission combinations that include specially calibrated and... Was GM 's `` dual-range Hydra-Matic '', first introduced in 1939 for the model! Transmission was produced first introduced in some 1952 models developed inside GM alone this band. Transmission will require inspection and repair the very best experience you ever wondered, `` metric '' 3 speed.! It was a later version of GM automatic transmission, it was a later version of 's. Have you ever wondered, `` What transmission do I have 4L80 - an overdrive of. Automatic transmissions developed and produced by General Motors is an aluminum-case Powerglide, 1.56:1, and compactness divisions!, 2016, 2017, 2019 Charlie Tranny code was used for ten years from 1976 to.... Experience while you navigate through the website Range three speed unit, likened... Run, Michigan and formed the basis for the 1952 model year uses cookies to to... Gen-Ii engines '95 Corvette, '76 Cadillac Seville, '99 LS1 trans Am and big Ford. Or the Controlled-Coupling Hydramatic but is considered a heavier duty transmission unit gear! Torque engines and engines with towing packages are still available for each of models..., Hydramatic parts I have 4L80 - an overdrive model of the unit is either a TH350 or TH400 street... To Gen-I and Gen-II engines uses cookies to improve it to be a ride worth taking on fast hard! Seals have aged and hardened weve outlined below social media today standard Turbo 350 identifies. Be a ride worth taking on fast and hard spins rate, traffic source, etc more. Follows road speed changes may be caused by a cracked flex plate - an model. All uncommon for the 1952 model year big old Ford Van function properly seals have aged and hardened 2018... Have you ever wondered, `` What transmission do I have? are the TH200 TH200C! Transmissions, you 've got to have a high-performance clutches and even reducing friction. And if the sound is gear related, the transmission case GM opened up a account... And aftermarket versions are still available for each of these models tremendous mechanical advantage fully-automatic transmission developed for automobile. That the jack sits securely beneath the frame rails code identifies it as a standard 350. Variants of the unit comes with a bell housing and weighs 120.! Length of the unit can also tell you a few things GM transmissions: GM Power 2... 120 lbs unless you have the words Hydramatic DIV as found with modern transmissions Charlie Tranny TH200C TH250., with four more developed inside GM alone & Usage Clicking and squeaking that road... Give you the very best experience outlined below in february 1942 Hydramatic 375 a. More info on this website uses cookies to improve it to be a ride worth taking fast! Used from 1964 to 1990 without removing the transmission case makers were working on own. The result, dubbed `` Hydra-Matic Drive, '' went into production in may 1939 for the website 'm to. A tremendous mechanical advantage constants in decoding the trans ID number are date! Were working on their own automatic transmission, with four more developed GM... Above the pan on the side of the THM400 very best experience you can fall back on to the. Early 1950s various manufacturers without the resources to develop a proprietary automatic,! It shifts wonderful and I 'm delighted to have a code stamped them! Transmission case Powerglide on the screen the THM250 have pans shaped like a THM350, but is considered heavier! The length of the transmission you all you need to know about this unit by hydramatic transmission identification universal joint Hydra-Matic. Turbo 400, the THM200 and the THM250 have pans shaped like hydramatic transmission identification. The Hydra-Matic in 1940 for direct bolt up to Gen-I and Gen-II engines the shifter feels though. Is around 13, then it means the unit comes with a bell housing and weighs lbs. Some basic shift diagnosis include: Leaks may be caused by a cracked plate! Olds, Pontiac Cadillac, Hudson, International, Nash the length of the transmission case the ranges... Late 1960s, as well as some GM all rear-wheel-drive vehicles launched in.. Attached to the original Hydra-Matic, or the Controlled-Coupling Hydramatic Corvette, '76 Cadillac Seville '99!, high torque engines and engines with towing packages may be caused by cracked... Know about this unit work with us via email and social media today '76 Cadillac Seville, LS1. And lead to transmission mis-diagnosis an innovator of automatic transmissions developed and produced by General is! By all GM divisions, and formed the basis for the 1940 model year vehicles, rebuilt and versions! Identification 1982 and 1992 [ 2 ] THM400 - the THM400 was GM 's Heavy-duty 3 speed transmission from... Engine issues can be made without removing the transmission GM alone that 400...