Does that input come from a module that monitors wheel sensors, or direct from sensors. Is one sensor enough or do you need 4/6/8? Why not figure how to add the sensor/s. Can't be that difficult to do with a little thought and engineering at this point.
Ken noted in his post that we had considered trying to generate a signal that simulated one or more wheel sensors. We also talked about trying to put some sort of sensor on the wheels, but that is a pretty big job. Adding complexity is what we think is the path of the data. We think the wheel sensor data might go to the Engine ECM (as part of the swerve avoidance/traction control) and then from there to the transmission ECM.
The best solution is to find ECM software from a transmission that was installed in a vehicle that did not have ABS (if there is such an animal).