The Hydra-Matic was even used in some later model GMC over-the-road tractors with the Pontiac V-8 in them. One torque-splitter version actually used two transmissions, one inverted above the other, with a special valve body that synchronized the shifting of both boxes simultaneously. The old 4-speed HydraMatic was also used in WW II military trucks and one version of a light tank with a Cadillac V-8 engine. My father's main competitor in the automatic transmission business in Nashville Tennessee in the very early 1950's was an ex tank mechanic who got his transmission training from the Army. They were the only two people in town who would work on automatics.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!