See Figures 1, 2, 3, 4 and 5
General Motors Turbo Hydra-Matic transmissions are used in all models covered in this guide. Through the years 1975-83, four basic transmission series have been used, covering four load capacities. The 200 series, which includes the 200C and 200-4R. The 250 series, which includes the 250C. The 350/375B series, including the 350C. And the 400.
Starting in 1984, most of the automatics used were in the 200 Series. The 200C offers a lockup clutch; the 2004R offers not only the lockup function, but a 4-speed, overdrive capability. These two transmissions are used through 1990. In addition, there is a 700 Series unit, known as the 700R4. This unit has four speeds with converter lockup.