This study investigated the tribochemistry of the adsorption of indigenous vegetable oils on steel contacting surfaces. Friction as a surface phenomenon has numerous disadvantages which include wear, tear and dissipation of heat energy, whose consequences in the automobile industry can be mitigated by lubrication. Wear, as one of the challenges encountered in the industry costs about 5% of Nigerian gross national product. Hence there is an urgent need for its mitigation. The nature and fatty acid composition of the vegetable oil is a factor in the extreme behaviour of the vegetable oil. Thus, watermelon seed oil which has the highest unsaturated fatty acid composition is expected to perform better than the mineral oil and the saturated fatty acids only on moderate loading conditions of 2N to 20N. But at extreme conditions of 120N to 300N, avocado seed oil) modified with an organic additive performed better than all the vegetable oils including the SAE10W30 mineral oil. The tribological responses (friction and wear) of the friction pair (AISI 52100 on AISI 8620) under modified lubricated conditions experienced a greater reduction in both friction and wear under extreme conditions.