Can a kinked trans cooler line cause engine overheating?

That kink is not folded enough to affect transmission fluid flow very much, if any.

And running without a thermostat doesn't cause over heating? My big old butt it doesn't. That's why it's there. To regulate flow and for quick warm up. Somebody needs to relearn how a cooling system operates. The radiator needs to be given a chance to do its job and running constant, unimpeded flow through it ain't how it works.

Why doesn’t the engine need to be given a chance to heat water up, since the radiator needs a chance to cool it down?