One of the most important types of misalignments is crooked ball bearing rings. In this study, effects of crooked shaft washer related to a single-row thrust ball bearing on the system vibrating response have been investigated. For this purpose, a new dynamic model including 4-dof is considered for this bearing, housing and shaft mounted on it. Contact forces between rings and balls are described according to Hertzian equation. In the following, nonlinear Euler’s equilibrium is used to describe dynamic motion of the rings solved by numerical method. It is shown that these responses contain frequencies and phases that support the specialized signature of crookedness of the shaft washer in thrust ball bearing. Veri!cation of responses has been done by Ansys software. The effect of amount of crookedness in the shaft washer and external axial force on the responses have also been investigated.