Such a great product name. Wiki:

Fluid Drive is the trademarked name that Chrysler Corporation assigned to a transmission driveline combination offered from 1939 through 1953 in Chryslers, 1940 through 1953 in DeSotos, and from 1941 through 1954 in Dodge models.

If you wonder how easy it was to operate in the early days, consult the lyrics of the WW2 hit G I Jive:

This is the G. I. Jive
Man alive
They give you a private tank that features a little device called "fluid drive"
Jack, after you revive

Chuck all your junk
Back in the trunk
Fall on your bunk