Are you installing the transmissions yourself?
On all automatics you have the front pump, this is the main pump for trans fluid, it is turned by the torque converter.
When you put the torque converter into the bell housing and into the transmission you have to line up the torque converter and front pump, they have slots that need to be aligned.
You turn the torque converter slowly while applying a little pressure, you will feel it click into place, keep turning and applying pressure, some automatics will click in deeper 3 times.
When bolting the bell housing to engine block they should slide together flush, you should NEVER EVER have to force them flush by putting in bolts and tightening them.
If you did then you broke the front pump.
Once bell housing and engine are bolted together the torque converter should slide forward slightly to be bolted to flex plate, if its pushed against flex plate and will not turn easily then something is wrong.
