John Deere AutoTrac automatic navigation system is an advanced and cost-effective navigation system. But this kind of systems is designed for John Deere’s tractor, it is not suitable for general vehicles. This paper proposes a mechanical modifications method based on XUV825i utility vehicle to solve the problem that ATU (AutoTrac universal) steering wheel can not be installed at utility vehicle. The mechanical modification method that installing a special joints between utility vehicle steering axis and ATU steering wheel can improve the concentricity, making utility vehicle under the control of AutoTrac automatic navigation system with high navigation precision. XUV825i utility vehicle’s structure is as same as general vehicles so that the mechanical modification method can also be adapted to the general vehicle. Finally, an navigation tests were carried out based on the modified utility vehicle. During the experiment, the path under manual driving was as same as the path under AutoTrac automatic navigation’s control driving. The average lateral deviation of the machine’s navigation path was less than 2 cm when the navigation system had been tested well and was working under the good road condition. This indicaties that the mechanical modification method is feasible and it does not affect the navigation accuracy of the AutoTrac automatic navigation system. At the same time, it shows that the mechanical modification method is applicable to general vehicles, that means, AutoTrac automatic navigation system can be used on general vehicles.