How hot should transmission fluid be after, let's say a 25mi drive on the highway?

My 77 300D is having no transmission problems and the fluid is warm after a highway drive, but not too warm to touch.

My 84 300SD will not shift into 3rd gear after warming up after a 25mi highway drive (but does fine in town). The transmission fluid was hot enough to be uncomfortable on my fingers after touching the dipstick.

I'm assuming the latter is not normal, correct?

The transmission's operating temp should be approx 80*C or close to 180*F. That's fairly hot to the touch.

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1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino

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