[U47]

In the original Type HydraMatic and 315 the flywheel flexplate / driven torus, drive torus and torus cover are bolted together as one unit. In addition to passing fluid energy from one torus to another they dampen engine vibration. When you pull the trans they are the first things to be seen.

In Roto HydraMatic the driven Torus and drive torus and multiplier are inside the transmission behind the oil pump. The Roto equipped cars have a real flywheel bolted to the crankshaft with a splined spring damper. When you pull a Roto and look into the bellhousing there is no fluid coupling and what you are looking at is the input shaft coming out of the front part of the oil pump and when you look the other way at the engine you will see the FLYWHEEL bolted to the crankshaft. Unlike a flexplate, this flywheel is a heavy unit, not as heavy as a stick shift Pontiac flywheel, but as heavy as a lightened racing flywheel.
The caption for Roto is; A three speed, four range HydraMatic.