hi,

basically gate exam is based on 10-12 subjects of your full 4 years engineering course. so you may understand that you dont need to study the full syllabus of engineering. you have to follow the strictly gate syllabus and study accordingly. now mathematics and aptitude is common to all. 15 marks from aptitude and english and 15 marks question would be from engineering mathematics. from this year question pattern  has slightly changed and there is multiple select type questions. so now coming to the subjects papers you have to follow the standards books. follow  our article to know about standard text book to prepare for gate mechanical engineering: https://engineering.careers360.com/articles/what-are-best-books-for-gate-me