Crankshaft Position Sensor (CPS). It just quit, I didn't exactly break it. But in a Jeep XJ it's hard to get to, and in my 63 rambler it's even harder!! Quit in the Rambler (with 4.0L Jeep engine). Had to have it towed home, luckily it wasn't far away. The speed sensor rotor in the AW4 trans I'm using in the Rambler is a PITA. Apparently it's lost its magnet, so no more speed sensor for the TCU. I have a manual shift box on it, have for the last 10 years or so. Can't seem to find that rotor new. I kind of like manually shifting with no clutch, so haven't taken the output housing off to see what happened...