Dynaflow was the automatic transmission used in Buicks from the early 1940's until l966

A.K.A Hydramatic, A.K.A PowerGlide. Also known as an Automatic Transmission. Hope This Helps.

Had mine done with a Bendtsens adapter sent it to his shop in Twin Cities Mn area. Had it done about five years ago it is outstanding would recommend it.

322 Cubic Inch (5.7 Liter) V8 producing 236 H.P. at 4,600 RPMs. 330 lb/ft of torque. RWD with 3 speed column shift manual transmission or 2 speed Dynaflow automatic transmission.

The Dynaflow in your '55 will launch in direct drive when the shifter is in "D". It uses a twin turbine torque converter with a variable pitch stator to provide initial torque multiplication. As you gain speed the stator pitch gradually decreases, effectively changing final drive ratio.

In concept it is sort of an early form of CVT. Power is transmitted through a planetary gearset which allows you to manually select low range. This can be used for quicker launches and for downhill engine braking.

This transmission was notable for it's exceptional smoothness.