The "flywheel" bolts together, with at least 20 bolts around the perimeter, IIRC. Some of the units have a square inspection cover at the top of the bellhousing, only visible if you remove the middle of the floorboard. The proper name for it is "fluid coupling" as it does not contain a stator to multiply torque. It does have the advantage of getting an almost 100% RPM lockup, not the built-in 10% slip of a torque converter. There's a big O ring around the outer edge where the coupling bolts together, and a hub seal like a more moderm torque converter has. It can leak at either, or both places.
Jerry
