My unit has just been rebuilt. The shift point is 5 to 7 MPH. I understand that the spring is incorrect and need a heavier one. I haven't taken a pressure reading yet. To have the 1-2 shift at 15-20 what pressure would be correct? Or what would be the correct dimension of the spring to use? Would going by a color on the spring help in selecting the proper shift point? All other shift points are good and the TV cable is set correctly. Just as a test I readjusted the cable by one and two clicks and it still shifts out at 5-7.