Electromagnetic vibration sensor

A drive line vibration sensor includes an emitter, a receiver, and a controller. The emitter and receiver are mounted in a differential manner such that drive line vibrations cause the emitter to vibrate at a different frequency than the receiver. In operation the emitter transmits a signal to the receiver such that the differential movement of the transmitter relative to the receiver produces a variation in the signal received by the receiver which is identifiable by the controller. In another embodiment, the emitter pulses the signal such that the frequency of the vibration can be determined. A recording device is preferably in communication with the controller to record the variation in the signal to provide an inexpensive diagnostic and maintenance system which can record the overall operation of a drive line under actual operational conditions.