What Lee is saying is good info. When you fit the torque converter to the box, Two shafts have to engage, first the drive shaft has to fit into the splines of the turbine. Turn the converter till the shaft engages and the box moves in a bit. Just like a manual box drive shaft engaging into the clutch plate.
Then turn again till the two lugs on the back of the impeller housing engage with the slots that drive the pump, in the front of the box. These are about 1/2" long and are only two, so you will have to turn the converter a good turn or so to get them to engage. If they are not engaged and you tighten the bolts it will push the center out of the pump.
If you have done it right, when you have tightened the bell housing to the engine, you will still be able to turn the converter freely through the starter hole or the hole under the car, then fit and tighten the bolts between the flex plate and impeller housing and your done.
All the best
Harvey.
