All the speed sensors are the same thing (pulse generator). Just find where the wires come out and check for AC (yes AC) voltage while things are turning. If they're not turning then the generators won't generate. He should be able to test them at the harness without cracking open the case. If he thinks he can bench test them by pulling them out, go somewhere else. The other side of this is the wiring harness. If a wire has been worn through then the signal can't get to the computer. You need a guy who can do electrical first, the Tranny is secondary at this point. First fix the faults, THEN if it still doesn't work, look at the larger components.