[evand4567]

We tested the resistance with an ohmmeter and found the degraded ones to be between .3 and .5, while the new CIM varied between 5-15 depending on it's position which is strange and I don't really understand what was going on.

Now for the unscientific part: we direct drove a wheel on and found a significant reduction in RPM noticeable to the naked eye. The sound motor sounded significantly slower as well.

That was enough for us to conclude the CIMs were bad, but if there's enough interest and I have the time, I can do some more specific and scientific testing of the motors.