So with the nut off the axle, the hub is still nice and tight in place. I didn't try pulling at it to remove it but it definitely didn't fall out on its own.
My setup looks different than that toothed nut that was posted, my toothed part is just a thin metal piece in that same shape, but doesn't have threads like that. My axle nut is the only threaded piece there. There is a washer, the big nut, that toothed thing, and then the cotter pin.
If my spindle is somehow behind this, what is the harm in putting it off? I can't afford the $500 price tag they gave me at the dealership right now.
Also, what else could possibly cause this grinding? It's hard to replicate and doesn't always do it...?