Why does it seem the ones that have went out have just gone out at once with no warning. Wouldn't it start slipping, or acting up in a way that would give you a heads up something is not right? In the past with bikes, quads and even a Jeep, l never have had one go completely out without knowing something wasn't right. I am fine if I have to cut a ride or trip short and limp it back to camp, but with no warning for it just to completely stop working is concerning.