DRIVING HISTORY, ONE MILE AT A TIME
Hydra-Jerk or Dyna-Slow?
An M-5A1 Stuart with Hydra-matic
The M24 Chaffee Tank
Oldsmobile ads said the Hydra-matic was the greatest technological advancement since the starter motor. For once, an ad didn't lie. Hydra-matic was an all-changing innovation.
In addition to the obvious convenience, Oldsmobile claimed the Hydra-matic was 10 to 15% more fuel efficient than a standard transmission. Largely due to a larger rear axle ratio than a manual transmission car. Hydra-matic cars, however, were quite thirsty in city traffic, but driving quietly on the highway could reduce consumption to 1 in 8 (12.4l/100km), not bad for a large American car of this era.
Regardless of the problems with the early cars, such as transmission oil curdling, engine surge and the tendency for abrupt hard shifts, the Hydra-matic provided simple two-pedal control. For American drivers, who were not enamored with manual shifting from the start, the Hydra-matic was a convincing advantage, even for customers who had previously been interested in semi-automatic transmissions.
GM's policy at the time was to give its divisions a year of exclusivity on new developments. As a result, the Hydra-matic was only offered on Oldsmobiles in 1940. Buick wanted nothing to do with the new transmission. Buick's developers called it the Hydra jerk. Cadillac did add the Hydra-matic to its list of options from 1941. Despite the high price, $100 for Oldsmobile and $125 for Cadillac, more than 40% of Oldsmobile buyers and about 30% of Cadillac buyers chose this new one. option.
As the Hydra-matic was no longer an Oldsmobile-only project, development and production was transferred to the new Detoit Transmission Division in March 1939. The first Hydra-matic was already delivered to Oldsmobile in October. When civil vehicle production was discontinued in February 1942, this new division had already sold more than 200,000 Hydra-matics.
The 1942 Oldsmobile proudly announces that it is equipped with the Hydra-matic transmission. Its chrome decals show this on both sides. 45% of new Oldsmobiles are now equipped in this way. Note the matte grille. Like many 1942 models, Oldsmobile had reduced the use of chrome as well as other limited use of zinc and other strategic materials.
battle tested
When the production of passenger cars declined, the American auto industry adapted and switched to the production of military equipment. The conversion was supervised by William 'Big Bill' Knudsen, who was president of GM from 1937 to 1940. Obviously, GM played a major role in the war. Ironically, 25 years earlier, Cadillac founders Henry and Wilfred Leland had resigned after then-chairman Billy Durant refused to be involved in military production.
The main tank in 1941 was the M-3 Stuart, produced by the American Car & Foundry Co. The M3, called 'Honey' by the British was mentioned, weighed 12.7 tons. It was powered by a 7 cylinder Continental W-670 radial engine with 262 gross horsepower. In 1942 the Stuart service in North Africa and the Pacific battlefield with the British Army as well as the US and United States Marine Corps
The petrol powered Continental engine was scarce, forcing Stuart to use less powerful diesel engines. At the end of 1941, Cadillac introduced a new M3 variant. The Continental engine was replaced by two standard Cadillac V8 engines with 150 hp and reinforced Hydra-matic transmissions, each driving a caterpillar track.
The redesigned tank, now called M-5, was produced from February 1942. Due to heavier armor and other changes, the M5 weighed 2100 kg more than the M3. With the two Cadillac engines, the top speed was equal to the M3. Around 6800 M5s were produced along with about 1800 M8 self-propelled Howitzers. She shared the chassis.
Around 1943 it became clear that the M5 was too lightly armored for the war in Europe. In April, Cadillac began development of a larger version, which shared the powertrain of the M5 but received a larger 75mm gun designed for the B25 Mitchell bomber. The new tank, the M24 Chaffee, went into production a year later. It was deployed on the front line from November 1944. By the end of the war 3400 had been produced. Some remained in use until the late 1980s. There were even a few derivatives that shared the chassis, engines and transmission. The M19 and the M37 and M41 Howitzer tanks.
Its use during the war brought no dramatic changes to the Hydra-matic's design. It has forced GM to solve the teething problems. After the war, Cadillac and Oldsmobiles used the slogan "Battle tested" in their commercials, which was true to some extent. When civilian production was restarted in late 1945, Oldsmobile also offered a number of modified automatic cars, especially for disabled veterans.
Hydra-matic is becoming commonplace
The Hydra-matic really took off during the post-war boom. By 1947, GM had already produced the 500,000th Hydra-matic.
Buick had a special drivetrain connected directly to the rear axle. Any movement of the Hydra-matic during gear changes would be felt throughout the car. This wouldn't go hand in hand with the smooth handling of a Buick. The other brands did not suffer from this because all movements were absorbed by the rear springs and by the universal joints. Chevrolet still didn't like it either and opted for the Powerglide, actually a simplified version of the Dyna-flow.
Pontiac embraced the Hydra-matic from 1948. It was extremely popular despite its high price. Hydra-matic cost $158.50 at Pontiac and $174.25 at Cadillac. 78% of Pontiac buyers bought it and 95% of Cadillac buyers.
In 1949 it turned out that being able to supply an automatic transmission was a great advantage, in fact, if you could not supply an automatic transmission it was a shortcoming. It didn't bother anyone that the Hydra-matic was not the smoothest and most economical, nor was it worth much in terms of performance. There were plenty of critics, but American car buyers accepted the negatives as long as they didn't have to shift gears.
Other manufacturers were soon forced to follow GM's path. Ford and Studebaker teamed up with Borg-Warner to develop a three-speed torque converter transmission. Packard introduced its own Ultramatic in May 1949. Chevrolet launched its first Powerglide in late 1949 for the 1950 model year.
Cadillac was the first to provide the Hydra-Matic standard on the Series 60 and 62 in 1950.
The Detroit Transmission Division built the 1,000,000th Hydra-matic in 1949. Dissatisfied with that volume, GM began signing contracts to supply the transmission to manufacturers who could not afford to develop their own automatic transmission. The first customer was Nash in 1950, then Hudson and Kaiser-Frazer in 1951 and Willys Aeros in 1954, and, oddly enough, Lincoln as early as 1949. In 1953 GMCs were also equipped with Hydra-matic and in 1954 Chevrolet trucks. Although Ford and Mercury had their Borg-Warner developed Ford-O-Matic / Merc-O-Matic, it was not suitable for the larger Lincoln engines with higher power. Most made no effort to hide the name and thus the GM origin, they were happy with the reputation and name recognition of the Hydra-matic.
Dual-Range Hydra-matic
The Hydra-matic went through a variety of minor changes throughout its life, the biggest coming in 1952. The 'Dual-Range' Hydra-matic was developed by engineer Kenneth Gage. There were now two shift patterns of which the second pattern, depending on the brand,
D3, D4 or S (Super) was called. Pontiac used two characters to the left and right of "Dr." Soon the names 'drive left' and 'drive right' were used. In drive right, the car would not come out of third gear until the car reached 72 mph / 115 km/h, just like at full throttle. Low was used to keep the automatic transmission no higher than 2nd gear until about 48 mph / 77 kph. Neither drive right nor low changed the maximum speed per gear, but it did provide great flexibility, especially in hilly terrain.
This 1952 Pontiac (see left photo) has the new Dual-Range Hydra-matic with two 'Dr' ranges. Oldsmobile called it D and S while other manufacturers commonly referred to it as D4 and D3. There is no Park stand yet and Reverse is still after Low. The latter eventually became the subject of a safety-related controversy in 1961.
Oscar Banker (patent holder of many vending machine related inventions and friend of one of the SAE board members) was mentioned in the book 'Unsafe at any speed' from Ralph closer. It was further mentioned that at an SAE presentation for the new Roto Hydra-matic, Banker asked why the NDLR shift pattern was still being maintained. Later, Banker wrote a letter to GM's head, Jack Gordon, explaining that it was dangerous and easy to reverse. was able to shift gears while the vehicle was still in motion.
GM replied that the shift pattern facilitates rocking the car when stuck in snow or mud. It was also indicated that millions of Americans were already used to the current order. Partly under pressure from Banker and other engineers, the federal General Accounting Office then pushed for standardization of the PRNDL shifting pattern for federal fleets. GM eventually agreed and applied the PRNDL pattern to all of its transmissions from the 1966 model year.
Hydra-matic production was interrupted by a catastrophic fire in August 1953, which destroyed the entire factory. It was one of the worst industrial disasters of its time with 6 deaths and $80 million in damage. To replace the factory, GM leased the Willow Run factory from Kaiser. This former bomber factory, which Kaiser acquired in 1945, had been out of service since June 1953 after Kaiser moved to Toledo, Ohio through the merger with Willys-Overland. The factory was modified in September. In November, GM bought the plant for $26 million. While Willow Run was being re-equipped, customers had to temporarily use a different transmission. Dynaflow for Oldsmobile and Cadillac, Powerglide for Pontiac. Borg Warner was called in for the non-GM brands. Deliveries resumed at the start of the 1954 model year.
By this time, the end of the original Hydra-matic was in sight. Customers were no longer so tolerant of the rough shifting while the nascent horsepower race would exceed the buckets' maximum capacity. In 1940, only a few cars had a power that exceeded 165 hp. For example, in model year 1955, the most powerful Cadillac had 270 hp. In 1952 Detroit Transmission began development of the thoroughly redesigned Hydra-matic which debuted in 1956.
In 1956 the Hydra Matic was completely redesigned so that all but one shifting (2nd to 3rd) was done by emptying and filling a second fluid clutch, eliminating the entire front clutch. All tires that worked with torque were eliminated, so no tire adjustments were necessary or possible. There was now only one friction circuit. The effect of this was a first to second gear sliding in before you noticed (still a very short gear due to the lack of a torque converter) and second to third with conventional clutches that was slightly better than the old Hydra-Matic, and a third to fourth that happened as quickly and as smoothly as pouring cold honey on your cornbread. Efficient? Barely. Slippery? Like a baby's ass.
The introduction of the "controlled coupling Hydra-Matic" in 1956 did not go so well. A lot of updates were needed. Most of these transmissions eventually came back to dealers for new front clutch covers, gaskets, and reverse cone clutches. By 1958 all issues had been eliminated. But by 1958, the Hydra Matic had competition. Chrysler's Torqueflight, released in mid-1956, was then considered a superior automatic. Ford's CruiseOmatic was a simpler version of the Torquelight. Studebaker used a similar Borg warner unit, and the Dynaflow, while not a model of efficiency, was still a pleasure to use in a large Buick. Released in 1964 in Buick and Cadillac cars, the THM 400 (Turbo Hydra-Matic) was an almost complete copy of the Chrysler design, as the 'Flush N Fill' Hydra-Matic was very outdated by then. .
7,000,000 Hydra-Matics
Oldsmobile president Charles McCuen, without whose enthusiasm the Hydra-matic could not thrive, was promoted to vice president of Corporate Engineering in August 1940. In 1947, he replaced Charles "Boss Kett" Kettering as head of GM's development division. McCuen retired in 1955 after a near-fatal crash involving a turbine prototype at GM's Milford proving ground. He passed away in 1975.
Earl Thompson probably left GM in the 1940s. He then started his own company: 'Earl A. Thompson Manufacturing Co.' in Ferndale, Michigan. Oliver K. Kelly succeeded him as head of GM's Transmission Development Group. In 1963, Thompson and his team received the "Elmer A. Sperry Award" for their work on the Hydra-matic. Thompson died in April 1967, aged 75.
Total production of the original Hydra-matic reached over 7,000,000 units. Most civilian customers switched to other transmissions in the late 1950s. Rolls-Royce built a modest number of 'Dual-Range' Hydra-matics for the Phantom V and VI up to and including 1978.
The Hydra-matic's influence far outweighed the number produced. It was not the first automatic, but it was the first successful fully automatic transmission that set the standard for powertrain development for decades to come.
Oscar Banker en het PRNDL-patroon
Oscar Banker (patenthouder van vele automaatgerelateerde uitvindingen en vriend van een van de SAE-bestuursleden) werd genoemd in het boek Unsafe at Any Speed van Ralph Nader.
Nader beschrijft hoe Banker tijdens een SAE-presentatie over de nieuwe Roto Hydra-Matic kritisch vroeg waarom GM het NDLR-schakelpatroon bleef hanteren. Banker waarschuwde dat dit patroon gevaarlijk was, omdat bestuurders per ongeluk naar 'Reverse' konden schakelen terwijl het voertuig nog in beweging was. Banker stuurde later een brief aan Jack Gordon, hoofd van GM, waarin hij dit probleem nader toelichtte. GM antwoordde dat het bestaande patroon voordelen bood, zoals het vergemakkelijken van het heen-en-weer schommelen van een voertuig dat vastzat in sneeuw of modder. Bovendien benadrukte GM dat miljoenen Amerikaanse bestuurders inmiddels gewend waren aan deze volgorde. Ondanks deze uitleg bleven Banker en andere ingenieurs druk uitoefenen, wat uiteindelijk leidde tot de standaardisatie van het PRNDL-patroon. Het federale General Accounting Office drong aan op het gebruik van dit patroon in alle federale wagenparken. GM gaf uiteindelijk toe en implementeerde het PRNDL-patroon in al zijn transmissies vanaf modeljaar 1966.
In augustus 1953 werd de productie van de Hydra-Matic abrupt onderbroken door een catastrofale brand die de volledige fabriek verwoestte. Dit incident, waarbij zes mensen omkwamen en de schade werd geschat op $80 miljoen, geldt als een van de ergste industriële rampen van die tijd.
Om de productie voort te zetten, huurde GM tijdelijk de Willow Run-fabriek van Kaiser. Deze voormalige bommenwerperfabriek, die Kaiser in 1945 had verworven, stond sinds juni 1953 leeg nadat Kaiser zijn activiteiten had verplaatst naar Toledo, Ohio, als gevolg van de fusie met Willys-Overland. De fabriek werd in september aangepast voor de productie van Hydra-Matic-transmissies en in november kocht GM het gebouw voor $26 miljoen.
Tijdens de aanpassingen in Willow Run moesten GM-klanten tijdelijk gebruikmaken van alternatieve transmissies: Dynaflow voor Oldsmobile en Cadillac, en Powerglide voor Pontiac. Voor niet-GM-merken schakelde GM Borg-Warner in als leverancier. De productie van de Hydra-Matic werd hervat aan het begin van modeljaar 1954.
Het einde van de oorspronkelijke Hydra-Matic
Tegen het midden van de jaren vijftig naderde het einde van de oorspronkelijke Hydra-Matic-transmissie. Klanten werden steeds minder tolerant tegenover het ruwe schakelen, terwijl de stijgende pk-race de grenzen van de transmissiecapaciteit overschreed. In 1940 leverden slechts enkele auto's meer dan 165 pk, maar tegen modeljaar 1955 had Cadillac bijvoorbeeld een topmodel met 270 pk. Om deze uitdagingen het hoofd te bieden, begon Detroit Transmission in 1952 met de ontwikkeling van een grondig vernieuwde Hydra-Matic, die in 1956 werd geïntroduceerd.
De Hydra-Matic werd in 1956 volledig herontworpen. Bijna alle schakelingen, op één na (van de 2e naar de 3e versnelling), werden nu uitgevoerd door het vullen en legen van een tweede vloeistofkoppeling. Hierdoor kon de voorste koppeling volledig worden geëlimineerd. Daarnaast verdwenen alle banden die met koppel werkten, wat betekende dat er geen bandaanpassingen meer nodig of mogelijk waren. Er bleef slechts één frictieschakeling over.
Het resultaat? Een overgang van de 1e naar de 2e versnelling die nauwelijks merkbaar was, hoewel de korte eerste versnelling vanwege het ontbreken van een koppelomvormer een beperking bleef. De overgang van de 2e naar de 3e versnelling was dankzij conventionele koppelingen iets soepeler dan bij de oude Hydra-Matic. De overgang van de 3e naar de 4e versnelling verliep echter buitengewoon vloeiend. Efficiënt was het systeem nauwelijks, maar qua souplesse was het een meesterwerk.
De introductie van de 'Controlled Coupling Hydra-Matic' in 1956 verliep echter moeizaam. Er was een groot aantal updates nodig. De meeste van deze transmissies kwamen uiteindelijk terug naar de dealers voor nieuwe voorste koppelingdeksels, pakkingen en conuskoppelingen voor de achteruit. Tegen die tijd had de Hydra-Matic echter te maken met stevige concurrentie. Chrysler lanceerde halverwege 1956 de Torqueflite, die algemeen werd beschouwd als een superieure automaat. Fords Cruise-O-Matic was een eenvoudigere versie van de Torqueflite. Studebaker gebruikte een soortgelijke Borg-Warner-eenheid en de Dynaflow, hoewel geen toonbeeld van efficiëntie, was toch een plezier om te gebruiken in een grote Buick.
Hoewel de Hydra-Matic in de jaren zestig nog verder werd doorontwikkeld, kwam er geleidelijk een duidelijke opvolger in beeld. Met de introductie van de Turbo-Hydra-Matic in 1964 verschoof GM naar een volledig nieuw ontwerp met een koppelomvormer en sterk vereenvoudigde interne werking. Deze transmissie zou uiteindelijk de klassieke Hydra-Matic vervangen in vrijwel alle toepassingen en markeerde daarmee het einde van de oorspronkelijke Hydra-Matic-architectuur.
De THM 400 (Turbo Hydra-Matic), die werd geïntroduceerd in de auto's van Buick en Cadillac, was vrijwel volledig afgekeken van het Chrysler-ontwerp, omdat de 'Flush N Fill' Hydra-Matic tegen die tijd duidelijk verouderd was.
7.000.000 Hydra-Matics
De directeur van Oldsmobile, Charles McCuen, wiens enthousiasme essentieel was voor het succes van de Hydra-Matic, werd gepromoveerd tot vice president 'Corporate Engineering' in augustus 1940. In 1947 verving hij Charles 'Boss Kett' Kettering als hoofd van GM's ontwikkelingsdivisie. McCuen ging in 1955 met pensioen na een bijna fatale crash met een turbineprototype op GM's Milford-testterrein. Hij overleed in 1975.
Earl Thompson, een van de grondleggers van de Hydra-Matic, verliet GM waarschijnlijk in de jaren veertig. Hij richtte vervolgens zijn eigen bedrijf op, 'Earl A. Thompson Manufacturing Co.', in Ferndale, Michigan. Oliver K. Kelly volgde hem op als hoofd van GM's transmissie-ontwikkelingsgroep. In 1963 werden Thompson en zijn team bekroond met de 'Elmer A. Sperry Award' voor hun baanbrekende werk aan de Hydra-Matic. Thompson overleed in april 1967 op 75-jarige leeftijd.
De totale productie van de originele Hydra-Matic-transmissie overschreed de zeven miljoen eenheden. Hoewel de meeste civiele klanten tegen het einde van de jaren vijftig overstapten op andere transmissies, bleef Rolls-Royce de Hydra-Matic nog geruime tijd gebruiken. Een bescheiden aantal 'Dual-Range' Hydra-Matics werd geproduceerd voor de Rolls-Royce Phantom V en Phantom VI tot en met 1978.
De impact van de Hydra-Matic reikte echter veel verder dan het aantal geproduceerde eenheden. Hoewel het niet de eerste automatische transmissie was, was het wel de eerste volledig automatische transmissie die commercieel succesvol werd. De Hydra-Matic werd daarmee niet alleen een technisch succes binnen General Motors, maar ook een industriestandaard die de ontwikkeling van automatische transmissies wereldwijd beïnvloedde. De basisprincipes van automatische schakeling, zoals hier voor het eerst op grote schaal toegepast, zouden decennialang bepalend blijven voor de verdere evolutie van de aandrijflijn.
