Here is an article from the old site I wanted to copy over here about the New for 63 Turbo Hydra-Matic in the Dec 1963 Motor Trend. I didn't have the actual magazine so ended up buying the entire 1963 Jan thru Dec Motor Trend set. (Some really cool stuff in these old magazines as most of you know.)
In reading the article theTurbo Hydramatic is basically the first GM transmission that marries a "fluid coupling" transmission (like the older hydra-matics) with a torque converter...which as the article states "can multiply engine torque both through gears and through fluid reaction in a turbine (the torque converter).
OK...here's the article including the front cover of the magazine.