I think your confusing bendix vs. solenoid. A bad solenoid will usually just click or do nothing at all. It's just a magnetic switch and either works or don't. The starter gear or what some call a bendix kicks into the flywheel and can work intermittently. If it gets sticky or the spring is weak the starter will spin without engaging the flywheel. That is what is wrong with your machine. So far as I know, there is no way to remove the cover and watch it work since the end of its shaft has to be in the flywheel cover in order for it to operate.It came with the new starter. I took the starter back off and inspected it and the teeth on the gear it turns in the trans. both good. It acts like an old chevy with a bad solenoid. Just spins.