Packard Forum Index » Post-War (1946-54)

Back in the day did people put overdrive on their cars with Ultramatics? Was there an overdrive designed to work with the Ultramatic? Curious more than anything.

I don't remember ever reading of any kind of overdrive that could be offered for use with a standard automatic from any mfg. Not because you could not install some kind of add on unit to the drive shaft but more because most if not all automatics have functions that depend to a large extent on speed or governor dependent hydraulic pressures for proper operation. There is probably someone who tried but I would think adding a separate overdrive that would change car or engine speed after the point where that carefully calibrated hydraulic pressure was produced could cause all kinds of shifting problems. Don't believe there was an overrunning or OD gear available on an automatic until the advent of the Automatic OverDrive transmissions in the 1970s or 80s.