I found a way to fix that, but that's another story.
I was dissatisfied with the factory shifts points from my very first drive in a TF equipped Mopar, a $50 Blue Greenish Poly Pushbutton'64 Dodge wagon, Custom 440 or something like that. I always had to explain it to people, "no it has a 318 but look, its as big as a 440" ;]
I just a) took the slop out of the kickdown linkage, and b) threaded it back until I liked the shift points under throttle, usually a long ways back, sometimes all the way to the end of the thread to make up for worn pivot points along the line.
The only downside to this is when taking Grandma to the store, low rpm/throttle application shifts can be a little jolting.
I just don't like shifts I can't feel.
I need to feel them and know what gear I'm in, and know my engine speed.
I've always needed to be super connected to the car like that, audio input, as well as visual.
I mostly always have the stereo off so I can think, but mostly listen to the car.
Wife and I drove all the way from WA to CA and best with no stereo in the car, trunk speaker wires in her car had been ripped out from loading firewood probably.
I'm super blessed/cursed to live at the bottom of a windy 2.5 drive up and out of a canyon, this is dirt and gravel. It's a road course. If we closed it down, we could do time trials on it, but as it is, you have to negotiate things like UPS drivers, even semis, as you're hauling @ss outa there - a well prepped Subaru helps - so it's real world driving, and a great place to manually shift your auto trans, as you need to be in a lower gear for better throttle response.
Coming down the canyon is always a downshift into 2nd gear to hold the car back, and just let it wail. On deccel, you'll find out if your valve guides/seal are any good, as you fly down the hill at near 4k RPM = roughly 40mph, with foot clear off the gas, correspondingly very high vacuum.
My first Subaru had an auto trans that refused to hold high RPM on downhills and most newer cars refuse to even engage a lower gear going down a hill, the gear will finally engage when you reach whatever piddly speed the car has decided is safe.
My current Subaru since 2017 is a 5sp, and I toggle back and forth between 2nd and third as needed on the way out or back in.
With a properly setup auto trans, you should have very crisp kickdown/shift, giving you a lower when needed, rather than having to do it manually, because then you find yourself running down the highway in 3, for a while, til you notice the tach needle is too high...
I recommend people leave it in D driving out and let the car sort it out, but in some cases, you have to select 2 yourself to negotiate things like hairpin turns on 15% slope and washboards, rocks the size of graprefruit or melons, moose, bear, and even worse people who hunt them and their stupidly loud pickup trucks.
