When you put the bolts in the flexplate for the converter did the converter spin easy to line up the bolt holes and have room to move back and forward in the trans pump . If not then you may not of had the converter seated all the way in the pump .when you put the converter back in the trans you did spin the converter to get it to drop in the pump .It should have went in 2 times spin and slide in 1 notch spin again slide in 1 moor time in the pump ears . if it didn't slide on and drop in 2 times you may have broke off the pump ears . that will keep the pump from building presser . then it is time for a rebuild