Below the Code Number stamping can be found The Transmission Serial Number. . The Controlled Coupling HydraMatic used 3. The three-digit production date begins with the first day of January 1969. Warner 4-Speed - Mid-1974 through 1981: Stamped at the left side on the top rear of the case. January 1 of 1968 would be number 366.
Turbo Hydra-Matic 700R4 - 1982: Code stamping located in the case on the right-hand side of the oil pan rail. However, plant variations have surfaced, particularly Fremont, where nothing seems to make much sense. Oldsmobile was chosen to introduce the Hydra-Matic for two reasons: economies of scale—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 of the new transmission. A letter designated the month and the model year was included. 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.
Dr Sport Coupe - 6. July 31, 1970 577 is the 212th day of 1970. The Controlled Coupling HydraMatic incorporated a secondary fluid coupling and a pair of clutches in place of the former friction clutch and brake bands, shifting in part by alternately draining and filling the secondary coupling. This weakness can be addressed by using an inexpensive aftermarket case saver kit. Unsourced material may be challenged and removed. This feature was not exploited. Designed for configurations, the series included 4 forward gears.
In 2001, an updated version — the 4L65-E, was introduced. But, they do not all bolt into the crossmember in the same space. Chevelle Nomad Station Wagon Series 3. By the time the 1954 models debuted in late 1953, Hydra-Matic production had returned to normal levels and all '54 model Cadillacs, Oldsmobiles and Pontiacs with automatic transmissions were once again equipped with Hydra-Matics. Shutting off the engine caused the transmission oil pressure to rapidly dissipate. 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.
There are a few things that all of the longitudinal gm automatic transmissions have in common. Muncie 4-Speed - 1968 through mid-1974: Stamped vertically on the right side of the case at lower rear, just ahead of the transmission extension. Arlington tends to code their 4-speed Muncies a bit different. 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. These can be identified outside the vehicle with the torque converter removed by a narrow front pump spline. It was an evolution of the , first produced in October 1963. At higher speeds, the rear pump provided all the oil volume that was needed to operate the transmission and the front pump's slide was nearly centered, causing that pump to produce little output.
Any Muncie build in calendar year 1969 for an August through December built 1970 model year would be dated with M, P, R, S or T Aug. Dr Sport Coupe - 6. The transmission would have four forward speeds 3. The Warner Gear transmissions will carry a production code number such as: Plant and Type - Month - Day - Year - Shift W - G - 10 - 3 - 1 The above designation indicates this 4-speed transmission was built at Warner on July 10, 1963—first shift. During the war, the Hydramatic was used in a variety of military vehicles, including the where two of them were mated to twin engines and the light tank. M20 - Four speed floor shift manual.
The last design change of the 700R4 was an added checkball to the valve body. Remember, a production date of 001 to 365 is calendar year 1969 and 366 or higher is calendar year 1970. Exception : 1964 were stamped on the left side of the case rear of the cover. Accurate coordination of these components was difficult to achieve, even in new transmissions. Since the three digit suffix is greater than 365, the date must be in calendar year 1970. The HydraMatic was designed to combine operation of a planetary gearbox allowing much shifting to be automated with a instead of a friction clutch, eliminating the need for de-clutching. 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.
If the production date is over 365, subtract 365 and find the corresponding Julian date for 1968. I covered Source Serial Number Code and Model Identification Code but not Production Code Number. Any Muncie build in calendar year 1969 for an August through December built 1970 model year would be dated with M, P, R, S or T Aug. Replaced in May 1979 by Turbo-Hydra-Matic 350. Turbo Hydra-Matic 350 - 1976-1981: Code stamping located on the right-hand vertical surface of the transmission oil pan. The first Oldsmobiles so equipped were shipped in October 1939. The output shaft was machined onto the rear unit and reverse unit planet carriers.
The car would then start to move, unless the transmission lever had been left in N, neutral. Please join in the discussion by. Also, the original Hydramatic required periodic band adjustments as a routine maintenance item that later versions did not. The Turbo Hydra-Matic 400 was introduced in the 1967 Chevelle and coding used a different format. January 1 of 1970 would be 366. If the selector lever was in reverse or moved to reverse after the engine stopped, two mechanical parts combined to provide a parking brake. In the end, the true Hydramatic was rendered obsolete because of its cost, both in raw materials used as well as the machining needed.
Introduced in 1939 for the 1940 model year vehicles, the Hydramatic was the first mass-produced fully automatic transmission developed for passenger use. Whether the Cleveland plant built any is uncertain. These still should give you enough information to check the transmission installed. 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. It was also adopted by Rolls Royce in 1991 and modified after extensive testing, and used initially in the Bentley Continental R, and subsequently other Rolls Royce and Bentley vehicles. This article needs additional citations for. I'm sure this info is already in here somewhere, but I came across this in the old threads and thought I may as well chuck it in.