if the vcm and/or ecm sees (or more accurately, -fails- to see) an incorrect or correct signal anywhere in the CAN, and both the dash and VCM are in the CAN, and the dash is where one of the 2 termination resistors in the CAN is: "P03= VCM Communication error P07= MP Communication error", {MP=Meter Panel} then the truck can do a number of things but I would not be surprised that not providing a signal to the transmission solenoids would be 1 of those things.
humor me, try a known good dash.
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