The results of the proton relaxation time dispersion measurements on Ge(CH3)4 at temperatures below 26 K show that the maximum of the TZT-1 dispersion curve decreased and the linewidth increases as the temperature is decreased. This cannot be accounted for by any version of the correlation function perturbation approach which at low temperatures, on tunneling resonance nω0=ωt gives a relaxation rate proportional to the correlation time. However if the tunneling linewidth is due to the torsion-torsion interaction-which is averaged out at higher temperatures-the observed behavior is explained. From the observed low temperature tunneling linewidth the torsion-torsion interaction in this material is estimated to be 30 MHz. The results of multipulse saturation sequence measurments at the maximum of the TZT-1 dispersion curve are presented and discussed in terms of a population-transfer model. © 1985 American Institute of Physics.