The work systematically studies synergistic effects of aminoguanidine-based ionic liquid (AO-IL) combined with ZDDP and MoDTC on enhancing the tribological performance of heavy-duty interfaces. AO-IL preferentially adsorbs onto metal surfaces, reducing contact with micro-asperities. This is attributed to its high adsorption energy on Fe(001) surfaces. Results indicated that the tribofilm exhibited a composite structure. The outer layer consisted of short-chain zinc phosphate, sp2 C and layered MoS2, which reduced friction shear resistance. The sublayer contained a rigid support network formed by the Fe3C phase that significantly enhanced interface bearing strength. Fe3O4 inhibited oxidation propagation through surface passivation.