I can’t find specs for the spring loaded plate that bolts to the flywheel. I’m not sure if the plate had incurred damage, and the springs are loose enough to rattle slightly when shook. Is this normal?
The problem isn’t the springs, it’s the wear on the plate itself. Look at the wear to the right of the spring at 12:00. That sheet metal cover is badly worn. Several of the others (at 4:00, 6:00, and 8:00) are also worn. You might be able to weld these up, but don’t weld the inner plate to the outer – that will defeat the operation of the damper. Replacement with a good hub is best if you can find one. I suspect the other side looks the same.
You can get rebuilt spring plates for your Roto 5 Hydramatic from Fatsco Transmission for $320. Core charge is $25 I think. I have bought 2 of them, they are fully rebuilt with new springs and welded back together.
Seals, filters, rebuild kits, etc also. http://www.fatsco.net/store.html#!/Roto-5/c/18246168/offset=0&sort=normal