it is not mechanical, this is an electrical fault
i would check the directional switch and transmission solenoids closely.
I know on some directional circuits they have diodes inline with the solenoids, i would check to see if there are any in the harness going to the directional solenoids and see if they are open or shorted.
According to how the ecm monitors these signals if they are open too long or activated at the same time for too long it will trigger this code.