One of the early steps outlined in the service manual for trans r & r is to support the rear of the engine. This can be accomplished from underneath with blocks or stands strategically placed, or it can be done from above by running a stout 4x4 across the fenders with short chains draped and fastened to the rear of the block. Otherwise, the rear of the engine will rotate downwards once the trans x-member and transmission are out. Its entirely possible that this step was ignored, which would have resulted in an unnatural mounting angle, pinched at the top and open at the bottom. If the trans to engine bolts and converter to flexplate bolts were then snugged without correcting the alignment issue, it stands to reason that undue stress and strain would have been exerted on at least part of the rotating mass. Its puzzling though. I mean, it seems like a pretty obvious gap in the pictures. What experienced wrench turner in their right mind would look at it, shrug their shoulders and say, "yep, that oughta hold 'er."?