Hi Tamil Amirtham. Thanks for contacting Careers360 and we hope we will be able to answer your query. 

For GATE, you need to give the exam for mechanical engineering (ME) as there is no separate category as such for automobile. So the syllabus is almost everything that you have learned in your four years of undergraduate course, or rather the mechanical engineering undergraduate course of four years.

The syllabus for GATE Mechanical Engineering is given here for your reference:

• http://www.gate.iitg.ac.in/Syllabi/ME_Mechanical-Engineering.pdf

Hope this helps you and all the best!