Very interesting.
As I was reading, I kept thinking "What is the difference between the Power button and this mod?"
Once done, do you still have the two settings, Power and not, just both firmer?
Signed,
Generally Mystified About Auto Trannys
;p
from what i can gather, the "power" button in 343's as well as the "ECT" button in the 442's DO actually change the shift points slightly (signal to tcm). it will wait to lock the TC longer, kick out of it easier, and hold rpm higher before upshifting. teh FSM gives the shift point deltas for ECT and normal modes for my '93. i have had little use for my ect button (i'm sure it's not as good as the later "power" button
