There's 2 types of bendix assemblies, one which works and the other which doesn't (sounds like a dead battery). The one which works has a tiny thrust bearing at the small end (which fits the hole in the cover). Both units have the same dimensions. There's not a lot of information on this part, and I figured it out by accident. Still not sure who makes the good units vs who makes the duff units. From a foot away, they look identical, but they're not.