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Turbo Hydramatic 400. Only those Chevelles I have documented via build sheet or other paperwork is listed here. There are certainly other Chevrolet models that may use the same transmission code tag. Julian date calendar - leap years (1964-1968-1972) - non-leap years. The Turbo 400 transmission was a 3 speed automatic transmission developed by General Motors. This was one of General Motors editions of the Hydramatic transmission series. This transmission is known more commonly by the name TH400, although it did receive another name change in the late 80s, adopting the name 3L80. The Turbo-Hydramatic 400 (TH400) automatic transmission can be found behind large, powerful engines on Chevrolet and GM cars and trucks from the factory, as well as Jeep, Cadillac, Oldsmobile and many others. While the unit is indeed one of the stoutest of its kind, trouble can. The Turbo 400 transmission was a 3 speed automatic transmission developed by General Motors. This was one of General Motors editions of the Hydramatic transmission series. This transmission is known more commonly by the name TH400, although it did receive another name change in the late 80s, adopting the name 3L80. The Turbo-Hydramatic 400 (TH400) automatic transmission can be found behind large, powerful engines on Chevrolet and GM cars and trucks from the factory, as well as Jeep, Cadillac, Oldsmobile and many others. While the unit is indeed one of the stoutest of its kind, trouble can still occur. Some signs of issues.
The 700R4 is a 4 speed automatic transmission, with a 30% overdrive in 4th gear. This transmission was produced by General Motors, but is also sometimes known by the name Hydramatic.
The development of this transmission was primarily targeted to improve fuel economy, and this was accomplished by a number of modifications, not the least of which was the 30% overdrive capability.
The 700R4 was used widely on both truck platforms and rear-wheel drive car platforms. Some of the popular trucks it was used in were the Chevrolet Blazer and Suburban and the Oldsmobile 350 diesel. This transmission was also used in the Chevrolet Camaro, Corvette, Impala, and many others.
Pros and Cons
The 700R4 was first introduced in 1982, and served as a replacement to the TH350, which was a 3 speed automatic transmission. As is expected with all new system, especially with such a major re-design, some design issues were present with the original release.
There was constant improvement, and by 1987 this transmission was much more robust and reliable. There was a name change to 4L60 that occurred in 1990, although this was essentially the same transmission.
In 1993 the transmission became electronically controlled, instead of hydraulically, and the name became 4L60E.
For the purposes of this article, the focus will be pre-electronic control. At this time, all of the regular 700R4, or 4L60 transmissions began to be phased out, and none are available in that format any longer.
This transmission was very popular and considered one of the best of ever produced. Two of the key reasons for its popularity were the improved fuel consumption and the 3.06:1 gear ratio in 1st gear. This is a much lower ratio than what was common, and provides good acceleration from a stop and is also good for off-road driving.
700R4 Performance Specs
As mentioned, the 700R4 was a 4 speed automatic transmission. When the transmission was renamed to 4L60 in 1990, this naming convention provided a number of key characteristics about this transmission.
The 4 indicates that it is a 4-speed transmission. The L denotes that the transmission is longitudinally positioned. The 60 indicates that the transmission is rated for applications up to 6000 lbs gross vehicle weight (GVW).
The amount of torque that this can handle will vary based on year of production, but one website states that the max engine torque is 350 lb-ft with a max gearbox torque of 650 lb-ft.
The gearing that was used was 3.06 for first gear, 1.63 for second, 1 for third gear, and 0.7 for fourth gear, essentially a 30% overdrive. The reverse gear in this transmission is 2.9.
The 700R4 case is a single piece constructed of cast aluminum. The transmission is 23.4 inches long and weighs 155 pounds. The transmission holds a total of approximately 11 quarts of transmission fluid.
The 700R4, produced by General Motors/Hydramatic, is considered one of the best overdrive transmissions ever made. This transmission was introduced in 1982 as a replacement for the TH350 transmission, with the primary goal of improving fuel economy.
This transmission had a lower first gear ratio, which was good for performance at low vehicle speeds, while the 30% overdrive provided significant fuel economy improvement.
The name changed in 1990 to 4L60, while the most significant change came in 1993 when the electronically controlled transmissions were introduced. This was essentially the end of the 700R4, or 4L60, as we knew it.
A THM 425 transmission, produced between 1965 and 1978, at the Ypsilanti Automotive Heritage Museum
|Body and chassis|
|Class||3-speed longitudinalautomatic transmission|
Turbo-Hydramatic 425 (TH425 or THM 425, later 325) was an automatic transmission developed and produced by General Motors. The THM425 was a derivative of the THM400; most parts directly interchange and some others will interchange with minor modifications. The internal parts spin the opposite direction in the THM425; the helical angle of the planetary gears is 'reversed' and the one-way clutches freewheel in the opposite direction, for example. The THM425 was developed for the 1966 Oldsmobile Toronado and the 1967 Cadillac Eldorado. A lighter-duty transmission known as the THM325 (using components sourced from the THM200) replaced the THM425 in both car lines after the 1978 model year. 1979 and later longitudinal enginefront-wheel drive vehicles used the THM325. The THM325 became the THM325-4L with an overdrive added in 1982, but all vehicles using this transmission switched to more-conventional transverse engine mounting in 1986. Bellhousing pattern used the 1967-90 Buick-Oldsmobile-Pontiac-Cadillac V8 pattern throughout its entire lifecycle.
Turbo Hydramatic 400 Rebuild Kit
- 1971–1979 Cortez Motor Home
- 1966–1978 Oldsmobile Toronado
- 1967–1978 Cadillac Eldorado
- 1973–1978 GMC Motorhome
- 1973–1978 GMC TransMode multi-purpose vehicle
- 1972–1978 Revcon motorhome
- 1989–1993 Vector W8
- 1979–1981 Buick Riviera
- 1979–1981 Cadillac Eldorado
- 1979–1981 Oldsmobile Toronado
- 1980–1981 Cadillac Seville
- 1982–1985 Buick Riviera
- 1982–1985 Cadillac Eldorado
- 1982–1985 Cadillac Seville
- 1982–1985 Oldsmobile Toronado
- ^'Hydramatic 375, 400, 475 & 425 Systematic Trouble Shooting'(PDF). 1973. Archived from the original(PDF) on 2017-09-09.
- Troubleshooting manual (1969)