you said that all of the cards were replaced. your problem makes me think but try to do this hint maybe it can help to solve your problem......
1. try to check the battery. short to frame test.
2. reconfigure the truck first maybe the speed limit is out of range
3. maybe the traction heat sink is short to the frame.
4. bad temperature sensor(drive motor,power panel,)
5. try to replace a good drive motor from the same unit.
6. and also the mast speed limit switches(check for continuity)


best regards and good luck!