Power hop is an unstable dynamic phenomenon that is observed on agricultural tractors operating at field working speeds under typical draft loads. This dynamic instability can be identified as a bounce motion preceded by an increasing oscillation in either the pitch or bounce modes. A definite and comprehensive correction or prevention strategy for the control of power hop does not exist. In this work a linear and a nonlinear model of an agricultural tractor were developed. The method of multiple time scales has been employed in the analysis of the nonlinear model. Numerical results have been obtained using Mathematica to verify that power hop can be modeled as a nonlinear oscillator. Solutions to the nonlinear model were obtained for several sets of system parameters. Parametric studies and frequency response curves were performed and investigated. iii Acknowledgments Thanks be to God, who loved us and died for us: " But God demonstrates His own love towards us, in that while we were yet sinners, Christ died for us. " Romans 5:8 Thanks be to my wife for her love, support, and encouragement.