My manuals don't say very much about this. When I went to get my speedo cable they gave me the wrong one. It would not fit into the modulator on the tranny. The car did have cruise control before I swapped in the 393 and TKO600. Do I still need the modulator? I took back the NON-cruise control speedo cable and got the cruise control speedo cable. It works fine, its just a tight fit and I think that is why the last one broke. The crossmember for the tranny is right next to it almost. Is the modulator only for cruise control cars? Can I take it out and put in the non-cruise speedo cable? Will there be problems if I don't hook up the cruise control wiring.... even though I don't have it anymore? I appreciate any help or direction on this.