In this paper is presented a study developed to monitor spur gears exposed to different kinds of failures such as broken teeth (incipient, intermediate and severe), angular misalignment and eccentricity. For every study cases RMS, crest factor and Kurtosis in the time domain are obtained and the spectrum in the frequency domain. The tests were developed in a test bed designed and built specifically to emulate fault conditions. The results obtained in the time domain shows up that the RMS value and the Crest Factor reveal a consistent behavior with the fault severity. Additionally, experimental results shown that the Kurtosis value barely identified consistently the failure caused by eccentricity.