The first of two papers in which a technique introduced by Resinous is used to obtain correlation function expressions for the coefficients of shear viscosity, thermal conductivity, and spin diffusion in normal liquid He3. The method involves matching the phenomenological and microscopic dispersion relations for hydrodynamic modes in the liquid. In this paper, the liquid is viewed as a system of two fluids with different spin components, and phenomenological expressions for the dispersion relations of the six hydrodynamic modes (spin is treated as a scalar) in the liquid are obtained.