I believe this was my problem, no meaningful pressure increase until more than 1/2 throttle which caused all sorts of part throttle drivability issues. The thing would shift to 3rd by 20 mph and would never kick down
Rebuilt 727 shifts but no downshift
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moes
Well-Known Member
I agree with everything you said, but what I’m trying to get across is if you don't have pressure right from the moment you're pressing the throttle; even if you fix all those problems you mentioned, you are going to have trouble. With the trans in gear, the pressure should start to rise as soon as the throttle is opened.
Now for my dumb question of the day- when i test the throttle pressure, what position should the shifter be in?
moes
Well-Known Member
I would put the car on jack stands, put the car in high gear and check to see if the pressure rises as so as you press the throttle, if it does you have it adjusted correctly. With the car off, check to see if you have the lever fully to the back when the carb is fully open. You should have the partial and wide open kick down working now. Take the car for a spin, see if you have partial and full throttle kick down, if not you have other problems. If the 1-2,2-3 shift points are where you want them, great, if not, then you can play with the adjustment a little to get them where you want them.
dvw
Well-Known Member
Pressure never rises with the crack of the throttle. The lever moves quite a bit before the cam on the throttle shaft ever contacts the throttle valve.
Doug
moes
Well-Known Member
With the trans in gear, the pressure should start to rise as soon as the throttle is opened. This assumes that the trans lever starts to move rearward with the throttle movement...there is no lost motion.
moes
Well-Known Member
I've always adjusted the kick down this way
This is from the Hot Rod article. The lowdown on stock Torqueflite kick-down. Check post #46
"If you adjust the cable so the lever is at the front of its travel range at idle, the line pressure will not increase properly as the throttle increases," Jason Muckala of Motech Performance explains. "This makes the trans shift too early, and it can cause the clutches to slip and destroy the transmission. I've seen people install springs to hold the lever forward, but it's not supposed to stay in that position at idle." This photo shows the lever full forward; in this portion of the lever's arc you can feel no pushback from the lever, an indication that no increase in line pressure is occurring.
Somewhere in this range of the lever's arc, you can feel a slight resistance from the lever's internal spring. This is where the line pressure begins to rise, ultimately causing a downshift. Properly dialing in the lever's range of motion is critical to shift performance and transmission longevity.
For the first half of its travel range, there is very little resistance and the lever does nothing. At the halfway point, you can feel where it starts to hit the valve inside the trans, and that's the position the lever must be in at idle."
dvw
Well-Known Member
Here is a picture of stock factory linkage. You will see the green spring holding the linkage forward against the carb stud in the closed throttle posistion. At this point the KD lever is full forward at the trans. Granted minor adjustments can be made. But during low throttle opening no additional throttle pressure is called for or used.
Doug
moes
Well-Known Member
Doug, I have my car set up the same way as your picture, but I have it adjusted like the way the Hot Rod article says, so when you open the throttle, pressure starts right away. In the 1970 Dodge Factory manual for a 383 motor with 3.55 gears, it states closed throttle shift point 1-2 are 6-10 mph and 2-3 are 10-14 mph. which I find very soft. My shift point 1-2 happens at around 20 and 2-3 is at 30. Nothing wrong with the way the factory has it set up, it works just fine, they do it that way to please everybody (grannies to the average guy). I've had friends that shave a little off their governor to raise their shift points, that's another way of doing it. When you raise the hp of a motor, which most guys like us do, increasing the throttle pressure right when you press the throttle it helps the transmission live longer, as the clutches will be slipping less on the shifts.
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