The Turbo 350 is GM’s three-speed automatic with no overdrive, used in rear-wheel-drive cars and trucks from 1969 through the mid-1980s.
For the full breakdown, see our best Turbo 350 Torque Converter guide.
Most people assume every “Turbo 350” is one transmission wearing different names. That assumption is exactly what turns a cheap swap into a pile of wrong parts. GM built the Turbo-Hydramatic 350 in several variants over its production run, and the differences between them matter more than the name stamped on the case.
In plain terms, what a Turbo 350 transmission is boils down to this: it’s GM’s three-speed automatic workhorse, introduced for the 1969 model year and fitted to rear-wheel-drive cars and trucks through the mid-1980s. Third gear is direct drive at 1.00:1, there’s no overdrive, and the 700R4 eventually took its place starting in 1982 because buyers wanted that extra cruising gear.
What The Turbo 350 Actually Is
The Turbo-Hydramatic 350 — called TH350 by GM and simply Turbo 350 by most enthusiasts — is a three-speed automatic transmission with a one-piece aluminum case and an integrated bellhousing. It was GM’s middle automatic, slotted between the two-speed PowerGlide and the heavier Turbo 400, and it became the default behind small-block V6 and V8 engines in Chevrolet, Buick, Oldsmobile, and Pontiac products.
Its reputation rests on a simple formula: light, compact, and tough enough for daily duty while still fitting between the frame rails of a full-size car. The integrated bellhousing is why a TH350 generally bolts up cleanly to the engine it was matched with, but it’s also the first place a swap goes wrong when the case pattern doesn’t