Not ever a stupid question. Each time we ask questions we learn something. Might be obvious to some, not to others. I had to think about it one day to understand what happens with a shift kit.
A shift kit is installed into the accumulators for the 1-2 shift and the 2-3 shift. The accumulators have a sealed piston in them. What appears to happen is trans fluid fills the accumulator to a point and then pressure makes the shift happen. The shift kit installs stronger springs and some spacers that limit the accumulator movement. By limiting movement..the shift happens faster and firmer.
