Trans problem

Alright I swap the motor out of a 2003 trailblazer 4.2
in-line six the motor runs great front diff u can hear
clock in and out but I can’t get it to move not in
reverse or dive or any gear there the trans reads on
the scanner and dose as it should checked fliud
levels or good hot or cold they stay the same it’s
like the fluid is not Circulating like it should any
ideals to point me in the right direction would be a
huge help

Ps all Connections r plugged in as they should be