So, those switches are only controlling EGR? And when they leak, they affect transmission shifts? Several forum members have replaced these switches to improve the shifts and eliminate the leak. However, they could have just as easily removed the switches altogether?

And, if there is more vacuum to the trans. after removing the switches, this can be adjusted on the trans vacuum valve on the I.P.?

Correct?

And, if I remember correctly, there are three plastic hoses going into the black box. One is vacuum supply. One is EGR output. What is the third? I seem to remember the third plastic hose heading back toward the IP for something. Could this be the modulation line that controls the function of the switch?