Recently the truck industry has experienced a large push to overcome the increasing demands of higher performance, lower weight, and longer life of components, all this at a reasonable cost and in a short period of time. Conducting experimental test in the early stage of design is time consuming and expensive. In order to reduce the cost, it is important to conduct simulation using numerical methods by software to find the optimum design. In practice, many of the finite element objects are very large so it makes a difficulty in meshing and also in analysis of the model. It very takes time and need a lot of memory of computer. Submodeling technique offer the solution about that problem. This paper presents the submodeling technique that applied on the corroded truck chassis.