Have you double checked the motor brushes? I have had some in the past that were right on the verge of stopping the motor entirley but would still allow it to spin but not tumble or vice versa.
Another thought that has come to mind is that this machine has a half field tap on the motor which would only be used during spin so I would check that all the wiring between the module and the motor is good and if so then it may be a faulty relay on the module.