Torque Convertor install question

There are 3 items that need to engage on a torque converter. #1 is the input shaft into the very center. #2 is the external splines off the front pump to the internal converter splines. #3 are the 2 'flats' (do they still use them?) on the external converter tube into the cooresponding flats which are part of the front pump. Install the TC without the input shaft to make sure it fully seats like that. If it does, your problem is getting the input lined up. Make sure the converter still wiggles easily BEFORE you tighten the housing bolts! (and after)