1979-1984 General Motors Turbo-Hydramatic 350C Service Manual Digital Download
The GM THM 350C (also known as Turbo-Hydramatic 350C or TH350C) was the version of the TH350 transmission equipped with a lock-up torque converter for better fuel efficiency.It was introduced in the late 1979 model year (some sources note it becoming more standard around 1980–1981 with electronic controls) and produced through 1984 for most passenger car applications. Some references indicate limited continued use in certain GM trucks and vans up to around 1986, but the primary production run for the TH350C ended in 1984 as it was phased out in favor of the 700R4 overdrive transmission.This distinguishes it from the standard non-lockup TH350, which began in 1969 and continued alongside the 350C variant until the mid-1980s transition period. Sources like Novak Adapt, Wikipedia, and automotive history articles consistently point to this 1979/1980–1984 timeframe for the 350C specifically.
