The time dependence of the vector and tensor polarization of a 270 MeV stored deuteron beam was measured near a depolarizing resonance, which was induced by an oscillating, longitudinal magnetic field. The distance to the resonance was varied by changing the oscillation frequency. The measured ratio of the polarization lifetimes is tau(vector)/tau(tensor)=1.9+/-0.2. Assuming that the effect of the resonance is to induce transitions between magnetic substates m(I), we find that the transition rate between neighboring states (+1 and 0 or -1 and 0) is four times higher than between the states with m(I)=+1 and -1.