Welcome to ModelEngineMaker !If you have problems registering or logging in, please use the contact menu option to request assistance.
In my line of (repair) work - you divide and conquer => is the error in the first or the last half, divide the half with the error, etc.So in line with all the good suggestions - disconnect the power train in halves - and since you only have a few parts still connected to the motor, with the problem still there - just continue dividing Best wishesPer