The Twins use a castle nut and cotter pin. Would that still benefit from your explanation?

Strange. neither my 13 nor 17 had castle nuts. they just had a standard flange nut with a cotter pin.

But yes- any ball joint or tie rod end that uses a tapered pin will work this way. shove the pin farther into the taper and it won't spin as easily. Once the nut is removed, then wail on the side of the knuckle around the pin with a hammer. a few good whacks will deform that taper just enough that the pin comes loose. voila.

Oh, I might have incorrectly interpreted the picture from the repair manual...

Nope, mine is a '17 and it had castle nut + cotter pin on a tapered shaft. Matt's may've been replaced at some point with the incorrect nut?

Very well coulda been. used cars and all that jazz.

That's always the way. I replaced mine with the setup from SPLParts, so now it's just a locknut. I put some paint on it to detect if the nut slips.

Same here. I alternate white, orange, and yellow paint pens as I do service work so it's easier to tell which mark is the latest.

Nothing wrong with the design, almost all ball joints have been that way forever. Sounds more like a corrosion issue or most likely an improper install issue. I have never had the taper fit break free before the nut. I would have tried to retighten or even overtorque the nut then heat/penetrant to remove.

Cross threading the worlds free loctite.