Phase transitions in poly(ethylene glycol) (PEG)-poly(vinyl acetate) (PVA)-toluene, PEO-PVA, PEG-toluene, and PVA-toluene systems were studied under static conditions and in a shear-stress field by the methods of cloud points, polarizing microscopy, X-ray diffraction, and viscometry. The application of a mechanical field was shown to increase the crystallization temperatures of PEG and PEO. It was demonstrated that the shape of boundary curves is changed upon deformation. The size of polyether macromolecules, the thermodynamic parameters of interaction between the components, and the orientational entropy of the deformed systems were calculated.