No vehicle uses the same flywheel/flex plate between auto and manual transmissions. They are physically and functionally (in terms of how they do the job) different. A flex plate is light, thin, and has a bunch of holes in it for the TC bolts to go through, as on a 4.0 is only 8 2/3" across. It serves no function as a momentum storage device, that job is done by the converter.
A flywheel is a wearable, friction surface kinda like a brake rotor. It is smooth on one side, has no holes aside from those for the crank bolts, and has enough mass to serve (along with the springs in the clutch friction disc) as the engine's momentum storage device. The 4.0's flywheel is 10" across.
If you need a flywheel just go to Napa. Don't waste money on a used flywheel. That's kinda like going out and buying a used brake rotor.
