Okay....let's start over......The burnt cable is the modulating cable to the transmission that adjusts line pressure to change the road speed/rpm for up shifts and down shifts.
The Kick Down switch is a electric button on the floor under the throttle pedal.
The fact that the transmission and the engine are bolted together has nothing to do with the ground circuit....at least, not in this case.
The engine and transmission are sitting on RUBBER mounts.
The only way current can flow to the assembley is through a ground strap which is mounted under the drivers floor and attached to the bell housing of the transmission.
Should the ground strap be missing or there is high resistence, the electricity will seek other routes to complete the circuit.
The battery has a positive cable going to the starter and a short ground cable to the chassis near the battery tray and hood hing.
The electrical power flowing through the chassis needs to complete the circuit to the starter and at the chassis to bell housing the ground strap is there to provide high amp's route to the starter.
Most starters pull 300 amp's or more when cranking an engine.
This ampage needs a low resistence path to flow through..or it will heat up the things it can flow through....much like electricity does to the heat bars that warm your room.......if the path is restricted, the amps will seek other paths to get the job done....in your case the cable to the tranny....and also any other gound path link it can find and in doing so heat the cable and melt the rubber sleeve.
Get under the car and check the ground strap.
