GM Full-Size Trucks 1980-1987 Repair Guide



Three automatic transmissions are used. The Turbo Hydra-Matic 350 and 400 were installed in 1980-82 models. Some 1980 and later transmissions use the Torque Converter Clutch system. Beginning in 1982 the 700-R4 4 speed automatic was available which has a torque converter clutch. The Turbo Hydra-Matic 350 serial number is on the left vertical surface above the fluid pan. The Turbo Hydra-Matic 400 is identified by a light blue plate attached to the right side, which is stamped with the serial number. The Turbo Hydra-Matic 700-R4 serial number is on the right rear of the case, just above the pan.