Friction tests were conducted with silicone fluids containing iron oxide particles to investigate the effects of friction and wear on the formation of a micro-gel in viscous couplings. Polysiloxane films were formed on the surface of iron oxide particles as sliding distance increased. The relative viscosity of the particle dispersion increased as well. Frictional heat had a significant effect on the formation of polysiloxane films which had an abundance of cross-linking and terminal trimethyl structures of polydimethyl siloxane. The iron oxide surface was indicated to participate in the tribo-chemical formation of polysiloxane films. A model anti-wear agent suppressed the increase in relative viscosity with less polysiloxane films formed on the surface of the iron oxide. The metal-to-metal contact between adjacent VC plates most likely generates chemically active iron oxide surfaces with frictional heat and wear, which promotes the formation of the polysiloxane film on the surface, leading to the micro-gel.