The kickdown cable is just that -- it opens up the pressure for the lines when you floor the accelerator, making the transmission downshift for passing maneuvers.
To adjust it, just take all the slack out of it at the throttle body side. I've read that some people just adjust the cable to WOT permanently and it still shifts no problem.
As far as resetting the computer, there is a fuse that you can pull, but I don't remember which one. The tranny won't go into OD unless the engine temperature is at normal operating temp.
