The present paper proposes to analyze relations between the behavior of two bodies in contact (local stress, vibration modes) and the rheology of third-body particles. Experiments are performed on a system composed of a polycarbonate disk in contact with a steel cylinder, where birefregent property of polycarbonate allows to observe shear stress isovalues. Multi-scale numerical simulations involve the coupling between finite elements and discrete elements to model simultaneously non-homogeneous third-body flows within a confined contact and dynamical behavior of the bodies in contact. Comparisons between experiments and simulations are performed on the dynamic response of the system, the stress distribution as well as the evolution of third-body particles within the contact. Such comparisons exhibit not only qualitative results but also quantitative ones and suggest a new approach to study in deeper third-body rheology.