Abstract: A drive line vibration sensor includes a housing having a strain gage attached to the drive line component, and an actuator disposed within the housing. In operation, the actuator exerts a force upon the strain gage proportional to acceleration experienced by the actuator. As the actuator is preferably a sphere manufactured of a low friction material, the friction between the actuator, strain gage, and the housing are minimized to improve the vibration sensor sensitivity. In another embodiment, the actuator is a pendulum attached to the housing by a pivot point having low friction bearings to reduce the effect of radial acceleration upon the measurement of longitudinal acceleration. A recording device is preferably in communication with the controller to record the pressure applied to the strain gage to provide an inexpensive diagnostic and maintenance system which can record the overall operation of a drive line under actual operational conditions.