[Tom Goldman]

The front pump bushing is a split bushing and is fussy about alignment.
even with the proper driver even the slighest misalignment will tighten the bushing to the point that the converter will not enter.
Also inspect the bushing for burrs or distortion at the edges. ....Some parts house bushings do not have much of a champher at the edge and burr easily when installed.
Also want to make sure the pump gear is not in backwards, as the drive tangs are offset in the gear.