While the trans is out you might want to check the alignment of the trans to the engine... . What you want to know is if the centerline of the crank and the center line of the trans main shaft are in alignment with each other...
If they are not it will cause the flywheel to be flexing back and fourth with each revolution of the crank... ... Kind of like using the flywheel as a universal joint ,,,,
If this is happening and you don't correct the problem. You will just keep breaking flywheels... .
the way you check the alignment is. take the auto trans apart and bolt the empty case back on the engine... . Then attach a dial gauge to the crank and have the plunger ride on the front pump bore... . Rotate the crank and watch the dial... . It should move more than . 002... if it does ... you will need to recenter the
plate on the back of the block... ... .
Look in an older Dodge factory service manual in the clutch section... . It explains there how it is done to a standard trans bell housing... . The procedure is about the same for an auto trans... .
Good luck... ///