Do the shifts complete quickly - meaning when it shifts from 1 to 2 or 2 to 3 - do the shifts elongate? or do they happen quickly?
please remember - this is not road speed, but how fast a shift takes to complete, it should be less than half a second at max. If its taking long then you can burn the box.
also please tell if this transmission has its own original torque converter? or was it piece mealed together by scrappie?